RE: Which engine (venus .40)
Just find out the weight of the engines you have and go from there. Nose heavy ain't gonna hurt you unless it's extreme.Better than the other way around for sure.
Compare the weights of your engines and look at the weight of the 46 Pro.I'd think it would be liter but heck,you already have engines.Go with it..
Let us know how you come out and what you choose.
Later
Walt