Quoted from pinheadpierre:2pac is the way to go. Others just aren’t as durable and lack the ability to bring out full color saturation to the degree that 2pac does. If it’s authenticity to the technology of the era you’re after, forget it. You can’t get whatever exact lacquer was used on your particular game and even if you could, you wouldn’t want to use it because it wouldn’t last as long and would yellow excessively over time.
I've used Minwax polycrylic water based for years and have not had durability issues, or any yellowing. Lots of people simply don't have the equipment to spray auto clear safely. You can spray polycrylic in the basement and there's basically no fumes at all.
The problem with the auto clear is the gloss. I guess you can sand it down some to knock the gloss out but EM playfield simply didn't shine like what you see quite often when people use auto clear. It's hard and durable, sure, but for a lot of us the problems just aren't worth it.