i'm converting a nitro plane to electric and need help with configuring the power and parts

the plane is mig-27 foam model covered with fiber glass. weight is about 10lb empty

as this is kind of a pig in the sky 1.8X1.7Meter i want it to fly as long as possible

for the moment the only information i found on net was this setup:

motor - hextronik hxt63-64b (280kv)

batt - 6s - which is good cause i already have 2 of those

prop - 20X8 - as my plane at the moment has no landing gear i thought about graupner cam folding prop

amp - 38.5

thrust - 6kg - which is kind of low for my plane (i guess)

any help regarding power setup will be much appreciated as i'm kind of new to the diy part of this great hobby and up until now i only had rtf planes