We don't have 45's in house, and I don't have their specs; sorry I can't answer. if you can measure your 45's OD, then we could look it up.
We didn't do any comparative testing against the Fuzion so we have no hard data to support any claims against the Fuzion. What you could do is lookup existing tests of the HK 3.0 vs the Fuzion in a 775 environment, and reasonably correlate existing data of XT vs HK.