Also, is the additional "punch" provided by the +P round significant enough to consider? If so, would a 147gr +P (if it even exists) be a good match of bullet weight + velocity?
I think that +p is worth the extra punch that it gives. As far as a bullet weight goes, I would stick with either 124 gr or the 147 gr. Depending on which worked better in your weapon (more accurate and reliable). You also have to consider controlability, however. If it's eaier to make follow up shots with a standard pressure cartridge, that is probably the way to go for you. Remember, it's all about shot placement, not cartridge power.
whats wrong with the Blazer Aluminum ?
I know some peopple have had issues with this in their gun, but it has always worked for me. YMMV