It's only your second table - you are still in the learning curve. Believe me, I've sacrificed more that 2 tables to get the wrap a rail the right way.
My suggestion is to stick with the 1" HD foam and put some muscle into wrapping the vinyl around the rail. I've built over 75 tables - all have 1" foam and have absolutely no "gramdma's toilet" feel to it.
You'll be sorry if you use anything less.
x2
Also, when was the last table you built? Jason (YAT) has this (relatively) new 65lb high density foam that is the nuts, it's really firm. I've used it on my last couple of tables, and coupled with really pulling tight it makes for a great rail.