It will help a little, but how are you getting on?
I find, that contrary to what many instructors say, many horses (especially cold back ones that don’t love it when you get on) do better if you place a hand on the very beginning of their wither and the other on the back of the saddle and get on that way. Many people think that hand on the cantle is the only way, but there are many ways to skin a cat and some horses definitely have preferences. Plus, having both hands on the saddle makes it prone to shift more.
Can you get a 3-step or a 4-step mounting block?
I feel for you, we have a QH who is rounder than a keg - any saddle slips on him no matter how tight the girth is done up. I use the neck hoist and tall mounting block method otherwise I’ll end up on the ground as if the saddle was mounted to a banana peel…