I have a 2 bladed Bruntons Autoprop on a 37 and find it ok but having had a Volvo 2 bladed prop on an earlier model 36 find that the Volvo prop was more responsive at lower revs.
    I put that down to the 37 being more than 1000kg heavier than the 36 so more power was needed from the same 29 HP engine.
    The best folding prop that I have had is the Bruntons Varifold and would not hesitate to have one again when the current one needs replacing.