I've been teaching sushi making since 1981 so I can give a little advice:
I have replaced my bamboo mats with silicon sheet for 10 years and there are also
plastic sushi mat available.
Usually my novice students manage to do the reverse sushi after 2nd try.
The way I use in teaching:
1. Get a large sheet of plastic wrap, 14x14" on sushi mat
2. Spread 1 cup of prepared sushi rice into 10x10 square
3. Place 2/3 sheet of nori on rice, place avacado, crab...