The Ruger 77/44 standard barrel is 18.5" long. 20-22" is a functional and balanced length for the Contender. 20" twist will stabilize 300 gr bullets very well.
I don't run an Encore, but this from DigitalDan sounds about right.
Does TC require a larger forend for that 44 mag barrel..?
If not, and it's their standard barrel contour, then because of the large bore it's going to be lighter than say a sub 30 cal. In that case, for the sake of ballance I can't see any reason not to run 22"