Just to give you as to how much thrust is enough, my Boomerang XL is 42 lbs on TO ( 50 oz smoke fluid included ) been pushed by a 27 lbs thrust turbine, carrying a gallon of fuel, the TO run is like 300 feet long to be on the safe side, climb out feels heavy but it is moving, climbing with plenty of energy, after 3 to 5 minutesof flying it is moving fast ( as fast as Boomerang can move ) it didnt have for ever vertical but it climbs high enough for me, landing is at around 34 to 35 lbs, dry weightis 32 lbs.
I have a Turbinator that I build some time ago from a kit, I'm estimatingdry weigh will be 19 1/2, the K85 will be more than enough for it to have fun for a while.