If I read this right you have 3 channel experience but you have 4 channel trainers? Just that alone should make you take pause. One steers with the rudder, the other steers mostly with ailerons. Maybe even on a different stick. Gas is going to be faster. Your depth perception with it will be off. People in my club have wrecked large planes going from small to large because of that. They are good flyers. Anyways, half the fun of flying is being around other people. Join a club and have someone help you for a few flights. Can't hurt and you'll like the club.