Hi mate i own both an hw99s and a tx200hc. If i was lamping i would take the hw99s as its lighter and easyer to shoot standing up, Although if you just want unbeatable accuracy while rested then you cant go far wrong with a tx200hc/mk111. I did look at both the hc and the mk111 and i fined the hc just balences better.
All the best PH1