Can't you use the throttle controls from the tir-hull? As far as bracket, I know for me an electric trim mounting bracket would be a must have, there no way Id pull my back out everytime I needed to lift that motor up to run, helper spring or not.
If you have an auto pilot, you could tye your kicker to the main engine with an easy steer setup. Panther steer.. they work but for me are a PIA, some guys love em. I have one I might do a deal on if your interested. I don't use it any more, it was perfect for handlining.
You will love the throttle master set up, if your handy you can make your own for pretty cheap, just buy the parts, do a little soliding, make a bracket and bingo.