Yep, I have a ripped up set of Morosos hanging in my shop to remind me to never spend $40 for these and try to use them with iron heads and/or stock valve covers. I have always used (before and after the Moroso debacle) Mr Gasket ultra seal gaskets glued to the valve cover with 3M trim adhesive. The yellow stuff that is like contact cement. I call it gorilla snot. No need to put anything on the head side. I also recommend cast valve covers no matter what gasket you use but a good set of stock covers is usable just more likely to resist sealing. Do not under any circumstance use anything like "Right Stuff" unless you're ok with using a BFH to get the covers back off. Do Not use Rtv sealants unless your ok with finding chunks of Rtv in your oil pickup screen.
By the way the gorilla snot also works good on oil pan and timing cover gaskets

I only run factory stock stamped steel covers, factory chrome on my 69 GTS 383 car, I used the black thick Fel Pro gaskets, glue them to the cover with ultra black and use factory hardware.

You need to make sure the rails on the cover are FLAT .

"Gorilla Snot" = 3M Weatherstrip Adhesive.
Not for stuff you might need to take apart later without shredding.
Back in the day, the SoCal off-roader guys (sand buggies, Baja racers) swore by it to keep the sand & dirt out.

that's why I only put it on one side of the gasket. It holds the gasket in place during assembly and prevents the gasket from squeezing out.
If you want something similar that comes apart a little easier try Edelbrock Gaskacinch.

Yes this works. Back in ancient times I had a fixture that allowed me to mill the valve cover rails on cast iron heads flat. I used to mill all the rails flat on the heads that I worked on. Some stock heads are WAY off of flat. Sometimes I would have to take multiple passes on the mill before they were flat, level and square to the world.