Like Gus said many times you cant get no more then 1 to 2 pos caster and keep the chamber in specs with stock control arms. I would think with tubular they could get more pos caster.
I also agree with Gus that I would sacrifice a little caster to try and get that left side chamber closer to 0 like the other side. Also I know many of the front end guys out there that are flat rate dont care what the actual reading is as all they do is get the reading to be green which means its in specs but could be on the high end. Its like if you had a chamber spec of 0 plus or minus 1 degree the car could have minus 1 degree chamber on the right front and plus 1 degree chamber on the left front and still show green on the screen and be in specs. But when you consider the true readings both front tires are leaning to the left side. I would never let a car go out like that but the machine would have the readings showing in the green which is in specs but both sides are at the far end working against each other. Same for caster. I like to get as much pos caster as I can to help the car handle better in most cases. And some guys learn how to use the machine but dont understand front ends to well.
Here is what a front end guy who worked at the Dodge dealer I worked at told me on day when a Caravan had just the left front tire worn on the outer edge. I told the service manager when we looked at the car and the customers complaint about the L/f tire worn on the outer edge it had to be a chamber problem as the R/f tire looked perfect. The guy they hired to do just front end alignments said to us it could be the toe on the left front ???? I said to him thats not possible because the front tires are tied together and both would wear the same and he still said oh no I have seen the machine show just toe out on one front tire but not the other ??? And I thought to myself........and this is the guy who should knows front ends inside and out. So I agree I would find a shop with someone who will set your car right and even if you have to slip him a little cash tip to make sure he does it right for you its worth it. Ron