hi guys

ive just purchased a bait boat hull.
i have 2x 1100 gph bilge pumps (forward thrust) and 2x 800 gph (reverse)
4x mtroniks viper marine adjustable speed controllers
spektrum DX5 radio set.
rc lighting 4 motor mixer
The boat is wired as in diagram but i am having trouble getting the boat to be controlled how its supposed to.
Is there a way of having the control i would like as in diagram, (i.e forwards/reverse on left stick and left and right by right stick)
by using another mixer or V tail mixing.
Please help guys as im really stuck