Just a thought. Wouldn't the incline of the new boot have just as much of an effect on skating slant as the holder? Seems to me the only way to know for sure what the problem is would be to bring the entire skate to your local profiler and tell them what you are feeling so they can profile what you are looking for into the blade.
Something else to think about. I always send my steel to NoIcingSports.com to get profiled. When I switched CCM Ribcore to True TF7 I sent the steel off and had them profiled exactly as my CCMs were, which is a dual 8"/14" and FBV 100/50 sharpen. My first skate was terrible, I felt off balance and timid with my edges. I went back and forth with noicingsports.com on possible ideas about what the problem could be, but THEN I remembered that I had forgotten to bring my Superfeet insoles over to the TF7s. Problem was immediately solved once the Superfeet were in the Trues. Edges were back and I felt planted.
What I'm getting at is it doesn't take much to throw off your MOJO. I'm 53 years old and need all the MOJO I can get.