i have the same problem sometimes. my coach said to just keep doing them and when you do a 1 3/4 to remember to pull in harder and twist faster and when i do 2 but fall to slow down a little bit and soon enough you will find a happy medium
I recommend focusing on the bhs before the double. The longer, more control you have going INTO the skill the more control you should have on the exit of the skill.
The twist accelerates the speed of the flip. The more twist, the more speed in the flip. It takes some practice to learn how to set the take off to control the acceleration combination of different twists and flips