I am working on both an 83 and an 85.
Windshield out of both right now.
I'm gonna need windshield rubber for both. I have original glass for both.
I'm also gonna be needing other weatherstripping for these trucks.
I see several companies that offer weatherstripping for these trucks.
I also hear many complaints about poor fit, and that most just relabel one company's products as their own at significantly more cost.
I do have plenty of new lock strip. Of which I've also heard compatibility issues with when mixing brands of rubber.

Is there an end all be all source for windshield rubber, door weatherstripping, and the felts in the doors?
I think my "glass runs" are good, I do have a few extra doors I can pirate from before I buy those.
But who's good there just in case I can't scrounge 2 good sets from what I have?
I do have a set of "precision" brand wing windows rubber, dies Steele and Metro products just repackage precision brand on those?
If every company just repackages precision brand I'll just buy those and bypass the higher prices of someone else's label.
But if there truly is a difference in these other companies offerings I'd be interested in other people's experiences with them.

Where does DMT fit in this mix? I know some of his offerings are admittedly just "precision" stuff.
I've gotten his heater box rebuild stuff and have been happy with those.

Who's the end all be all best option for these parts?
And before someone mentions LMC. Screw em. Not interested.

For my 79 I bought all the door and door glass stuff directly from precision. It's been a few years since I bought it but that was the best price and it seemed like everyone was re selling their products anyway like you said.

For the windshield seal it seems like no matter who the manufacturer is there are complaints. But from what I remember from posts here that might be more due to the thickness of the new windshields more then the seal? I'm sure there will be more comments on that.

Might try restorationspecialties.com - they have a huge variety of stuff and good prices.

Windshields: on my square-body K10 years ago, it took 2 different brands to get one that fit, which was a Pilkington.
GM made - what, 60 billion of those trucks ? - wouldn't think an accurate size would be difficult...

I hope so.
and if it comes out that "everyone" basically resells Precision brand seals so be it. Ill just get straight from them.
If Precision has the best of one seal and metro or soffseal or Steele has the best of something else thats OK too,
Also I heard somewhere that the seal made for a 92-96 Ford F series actually fits our trucks better that have a slider window, but have never tried that. Any truth to it?
both of my trucks have solid back windows now, I have sliders for both. I do have original seals (though used) for both sliders I have to go in those trucks.
I have an 85 that is still "all" 85, and an 83 that will be getting a '90 rust free cab that I have. Glass is "out" on both, right now.
on the 83 when it had its original cab I replaced the door to cab seals on it probably a dozen years ago, that cab with those seals is long gone.... I dont remember what brand of seals they were someting I ran across on feebay back in that day.
The 83 with 90 cab will probably be first. I have been talking with a couple of people with "dustless blasting" and a painter buddy of mine about that one right now..... the 85 might go back together "as is" as I have the dash out of it and the windshield. in process of replacing heater box with a "factory AC" one and cut holes in its dash for the original face vents and putting it back in.... Id "like to" get that one painted as well down the road. I bought my heater box foam (gasket set) from DMT.

For what it is worth, I have not heard of anyone that did not have issues with sealing the windshields on the 72-93 truck cabs. They all leak if its not the original factory seal, but by now I'm not sure I would believe that either.

Yes!
Detroit Muscle Technologies: https://www.detroitmuscletechnologies.com/

https://www.detroitmuscletechnologies.com/81-93/

I've seen his display at Indy spring swap the past few years and some of what he brings is still in "precision" packaging.
I can get that stuff cheaper right from precision. But y'know he has some stuff that precision doesn't have. That stuff is be interested in from him
I wonder (it would be nice if he responded here) if he could put together a package deal of everything that he offers for these trucks including the rubber inner wheel well extension and the rubber baffle for around the radiator, a heater box kit (at least) for a better package price than what the individual prices are for each individually.
I bought an ac box kit for the 85, I'm gonna need at least that for the 83.

Anyone have any experience (good or bad) with either soff seal or metro or Steele?

I've never replaced the slider seal but my understanding is that the factory one uses a special seal and the aftermarket ones use the same seal as the regular glass window.
Mine has a factory slider buy I picked up a good looking aftermarket one from a junk yard pretty much for that reason.

I knew of 2 but taking stock of what I have I see I have 3 sliders of which among them are 2 different types of seal. Have to look at the 2 that are the same as each other but their seal is more compact and seems more "built in" than the other one of which I know to be a factory original. That one came from a well known member here, who used to host a swap in Rockford IL around April... I think that one takes the lock strip to hold in like the front windshield does ...
I definitely remember seeing the mopar factory stamp etched into one of the pieces of glass that makes up that slider assy. I guess I'll have to take my chances with the respective used seal on whichever ones get put into my trucks...

All 3 but on different vehicles, it's a roll of the dice. But I will say Steele stands behind their products