Trials Tires Questions

I was just reading the recent thread about the Hoggy G and how it compares to the Fireball. This raised several questions in my head. First, which works better for trials a tire with a round or square profile? I’m thinking mostly in terms of grip and bounce.

How much does the tread pattern affect the tire’s performance (nubs vs. smooth)?
How well do the different tires wear compared to each other?

The only trials tire I have used is the one that came on my Summit. I was surprised at how high the tire pressure I needed in order to not roll the tire. Would a rounder tire be less likely to fold at lower pressure?

Are there any specific tires that anyone would recommend?