I will keep the weight to 1:1.5 to 2 ratio. For high lift airframe, you can go to as high as 1:2.5. That's it, 14lbs turbine will power a jet up to 2.5 times its thrust rating. 1:1 ratio will give you ballistic performance. I fly my Avonds F15 at 8kgs and F9F Panther at 11kgs with 5kgs thrust turbine.

B777