Hello Backfired
cg as per manual cg is measured from the leading edge of the top wing
25% 3-5\8 GOOD PLACE TO START
30% 4-1\8 better elevator responce and quiker snaps
35% 4-5\8 approach this cg with caution
thrws are
aileron 5\8 up snd down
elevator 3\4 up and down
rudder 1-1\4 left and right
as for servos,i just used standard 3004 futaba servos but thats really a builders choice issue.same deal for placement,i prefer to put servos as close to the control surface as possible
and the tank,also a builders choice issue,i stuffed foam paddeng around mine,never had a problem
anyways, hope this helps,and good luck on your new plane