Have flown a similar Kadet Senior 78" and Seniorita (equivalent to your Tele 40) with a Saito 52 4 stroke. Both did very well. 50 2 stroke will work fine but you will spend a lot of time throttled back.

For the present, have a 40 sized Funster ARF (upside down Telemaster) I will power with an EFlite 46 electric. Plan to finish mounting a Saito 90 twin on my Senior Telemaster.

Tom