It is hard..I can only do it for a little bit. I think the reason it's so hard is because when you 2-point you use your stirrups to push your heals down to anchor your leg. Without stirrups there is nothing to lean on to push your heals down.
Since December I havent ridden with stirrups lol ( on 2 of the 4 horses - the baby and the bucking pony with the saddle so old the leathers wont go back on are excluded) ;p
I can do jumps and courses. It's hard work and faults I have with stirrups are even harder to fix without! Lol But I think it has hugely improved my position! :)
I decided today to really commit to doing no stirrup work and riding with shorter stirrups/going around in two point, needless to say I am ridiculously sore but excited to be getting back in shape! The only complaint I have is that it kills my right knee, I'm hoping that will get better too.