Might have better luck posting this in the coaches forum or the Q&A forum. Coaches (unless they're moderaters) can't post in this section. Feel free to start a thread in either of those sections, or let me know if you'd like me to move or delete this one.
first of all, don't worry, i swear giants get easier. and i bet everyone has told you that and you cant imagine them being easy. but seriously they get so easy.
second its hard to give advice without seeing it. but if you tap where the low bar would be it should be okay. and they might feel jerky but they really aren't. like it make be that you think its bad but its really okay and you'll just have to get used to them.
Giants used to be soooo hard for me because I couldn't cast hand so i would really have to work hard on my tap but now I do the straddle cast and its a lot easier so now giants are easy and I heart them!!!
Have you ever tried doing giants from a tap swing (with no cast)? We used to do a drill to practice our tap, wrist shifting, and pulling our toes over by doing giants from a tap swing. Now, the giants didn't go to handstand; they generally pulled over the bar to push up shape, sometimes higher. Doing the giants from the tap swing required a harder tap and pulling our toes over the bar harder. I found that after doing these, it was much easier to do giants after a nice cast.
At first, I had problems with my giants also. and they do get easier so no worries. but i think one of my main problems was the swing down from the handstand to the tap... i would arch down instead of staying hollow. so now i stay hollow on the way down and it allows more tap as well. i <3 giants!