dman
Your limited to 35lbs of thrust whether the airplane is 35lbs or 50 lbs. Your best best is two turbines of equal thrust on the two inboard pylons(Turbine A + Turbine B = 35 lbs). The rest of the engines would be dummies. You could also get 4 SimJet 700 turbines(7 lbs thrust). The other option is to build the plane as you wish, find a non-AMA site where they will let you fly, get your own liability insurance and go for it. However, this means that you would never be able to fly it at any of sactioned jet meets.
Turbine is in your court...
Ed