Standard servos work fine on my STele, which is powered with OS 70 Surpass. If you fly it at trainer speed (i.e. not fast) and not excessive control throw (maybe 20 degrees on elevator, 15 degrees on ailerons, 30 degrees on rudder) then 40 in oz or so is more than adequate. Sr Telemaster is kitted for ailerons.

I had a heavy STele picked up at auction, same size & planform as my Hobby Lobby kit but built with lots of lite ply sheet stock where my kit was built up sticks. The auction job weighed 15 lbs compared to my Hobby Lobby kit at just under 10 lbs. The auction plane came with Supertigre G-90 power and 1/4 scale servos, which it needed at that weight and power.

It is the Senior Kadet which is kitted for three channels/no ailerons, to which many add ailerons as a builder mod. The Telemaster & Kadet are sometimes confused (two alltime great big trainers).