I have a frozen shoulder on my lead side at the moment so cant push up out of a heelside sit. I have forgotten what a pain toeside launches were. Keep working on the heelside launch. It is really a matter of core strength and balance. Yoga or pilates are probably your best conditioning for off the mountain. It is also a lot easier to get up heelside when you are on a slope so try dropping your legs over the lip when you strap in.
This is all preference. I like toe side launches better.