Replying to Tubes vs. flat bars for learning

I have a 14ft 8 inch tube and then a 10 ft double barrel with two 5ft extensions. My question is it easier to learn on a tube and bring it to the skinnier rails or vice versa? So far it seems that I have a harder time gripping the tube when going for fs spins vs. bs spins. Another question I have is kinda off topic here but with my stance I have my feet about shoulder width apart and kinda equal weight between my feet. The problem is when scissoring on something wider I can't dig my inside edge in as easily or at least I think I can't. So how should a good stance look and feel like? +K to helpful answers