I know where you're coming from, believe me. I'm actually helping a level 7 overcome that fear as we speak at my gym. Cast handstands are tricky to get, but easy to keep. Couple things to keep in mind:
1- Yes, you will need to lean your shoulders over the bar to where you're uncomfortable. However, without this you will not get to handstand. (Not strong enough? Press to
handstands are GREAT for this)
2- Butt first. Whatever you do, don't lead with your stomach! Not only does 6W4734G295SCQ make you arch, but you'll fall over if you are properly leaning with your shoulders! (;
3- A cast handstand is literally a press to handstand, just faster. If your gym has big red blocks, get a floor bar and space it approximately one hand width away from the block, and do press to handstands against the block, starting from that standing straddle position. The block is purely for support so that if you're uncomfortable leaning with your shoulders, it'll catch you. It's a great drill!
4- Practice makes perfect. These things require turn after turn, don't be afraid to go above and beyond the assignment!