Hey Charlie, welcome to the board......well this side of it anyway.
If your pouring your own, I HIGHLY suggest getting over to the Castboolit Group Buy forum and see if you can touch base with Mihec and pick up one or more of his 640 designed molds in .41. He might have one or two sitting aside. He also has a SWC which was put together by deminsions from the members using Keith's designed original molds. It is a great shooter.
Now this said MP molds aren't cheap like Lee they are precision made brass in 2 or 4 cavity. THey usually have at least three pin sets that are offered, you ight as well get them all and be did with it. This alows you to pour up a solid using the blank pin, and up to three different HP nose depths or diameters as well using the same mold. So it is like getting 2-3 molds in one. The Penta pins aren't the greatest as is, but I found that by chucking them into my drill press and filing off a portion of the tip it gives more or less a nice cup point which does work much better IMO.
Otherwise for what you DO have coming, I like to use the alox blend of 45/45/10 myself since it dries and isn't sticky. I have run it up into the upper 1600 to low 1700fps range thorugh my 454 with a double dip, once before sizing and once after. The weights between the 195 and the 220'ish range are where I spend most of my time. I DO have the heavy 240gr mold but to be honest I have only poured up one batch of around 250 of them just to try them out. I shot maybe 30-50 of those and the rest went back in the pot. I just couldn't see, #1, it doing anything for me that I couldn't get done with the others, #2, I didn't want to run a GC unless I really needed to.
I really do not like posting loads when I am not sitting in front of my data but of the powders you listed, Unique is one that I have used. My primary powders are AA-5,7, & 9, with 2400 and 296 falling in there with those. I like these due to they meter very well and give good velocities with everything I am running. I just got done with sighting in my Redhawk to some of the MP bullets yesterday as a matter of fact and was loading 19grs of 296 under the MP 413640 which drops at 220 with the lg hp and around 225-230grs with the small one depending on the alloy. I REALLLY like those molds and that bullet in particular. IF you wanted one mold to which you could cover most of the things in the lower 48 with that would be it. The solids have a nice fat meplat on them and the HP's well if your alloy is right they roll back like the small atomic bomb clouds. This is a pic of my .452 bullets which are almost identical only larger to the ones I described above,
THe alloy I am using in those is softer than what I have to run in the magnums and trhose were top end RUGER ONLY loads with that alloy so they flattened out a bit much. The best part of casting, well, one of the best parts anyway is testing what you've poured up to see how it preforms.
I'll shoot you a note after Christmas with a little more info if you want. Right now I am sitting at the farm with the grandkids getting ready to head out and see if we can find a pig to cook for Christmas dinner.
Merry Christmas
(oh, and the thread listed above on the 41 Club, yes by all means spend a bit of time reading through it.)