The Saito 65 weighs as much if not more than a saito 91. It weighs much more than a Saito 72.

The better comparison would be to compare the Saito 72 with the OS 70 for 4 strokes. The Saito weighs a little less.

The OS 50 SX would be a good two cycle choice but there's also the Magnum XLS 52 which costs much less and is a very good engine.

Typically, the 4 strokes have more instantanious torque and this works out better for 3D

Actually, if you purchased a Magnum XLS 52, or Irvin 53,or OS 50 SX, or the Saito 72 or OS 70 Surpass II, you will be pleased with any of them for your purpose.

Enjoy using RCU,

Jim