If you want to use the adjustable sights you can change the original rear sight blade to the shortest one that S&W offers. That will reduce the height requirement for the front sight. It will not be a huge change, but every bit helps
I have the 45 LC variation of that revolver
I have also bought some spare barrels because I want to do an adjustable sight version of the revolver. Like you I plan on using a steel 625 as the donor, but mine will be in 45 LC