I have a 625-8 PC and have not tried the two bullets you have available but use the powder you will use so for what it's worth here my experience.
I have only tried two bullets and about 4 different loads in the 625-8. I found all shot equally well which was very good. I have no formal groupings or chronograph data. Neither of these load left the barrel dirty or leaded up the barrel but did leave debris, not so excessive as to cause a problem, in the forcing cone that required a little extra effort with a brass brush and Hoppe's No. 9.
Xtreme plated 45-200 SWC (i.e. copper plated, 200 grain, semi-wad cutter, diameter 0.451)
Missouri Bullet Company coated ".45 Button - Hi-Tek" - 185 grain, 0.452 SWC, Brinell 12, optimized for Bullseye Shooting
I started with the Xtreme product but the Missouri Bullet Company product seems to shoot better (maybe?) but I have no objective data to prove it.
I have used both HP-38 and W231 powders (essentially the same powders) and have had good results with 4.6 grains of these powders with either bullet.
Here's a link to the Hodgdon reloading data website which I have found to be a reasonable resource for .38 special, .45 acp, .44 special, and .44 magnum load.
http://www.hodgdonreloading.com/