I have a Futaba 9C transmitter, which is great for first flights because it has the slider controls on the sides of the Tx. These are little rotary knobs that are positioned to be under your index fingers. My little trick is to program one of them with about a 10% mix to elevator. In effect, that turns it into a second trim switch for elevator. With the mix, you can determine how much trim is available on the slider. I usually set it to have about 2x the amount of travel that the regular trim does. This gives me some advantages:

First, it's under my finger and I don't have to hunt around for it while I'm struggling with a snake-dancing airplane. No need to take any fingers off of any sticks while flying.

Second, it's more powerfull - or as powerfull as you want it anyway. I find that new airplanes need just one click more trim than the regular switch can give me

Third, the trim change is effective immediately. WHen the plane is trying to hover itself on takeoff, just slap that switch over and whamo, you got trim. Trying to punch the trim switch 18 times is again, too much for a test flight...

Once everything is set up, I deactivate this mix, as there is the risk that inadvertent deployment during sport flying would send the plane into the ground.