I was using the 32-20 as an example because of case size and low pressure characteristics. Showing which powders are preferred at lower pressures and at the low pressures we are talking about. A jump of 60grs in bullet weight combined with the "relative" large capacity of your case with inserted bullet in the range of 2 to 5grs of powder I do not see a problem if you back your charge down a bit. Starting very conservative.You have enough experience with bullseye (using it's burn rate) and your chrono to get a feel of internals. I think you can get the obturation and keep it well under 26k psi. As far as loading density goes, the double base powders with higher percentages of nitro will be more forgiving. 5744 and Titgroup are great for low loading densities. As is a few others. 5744 has been proven to have nonexistent variations in burning relative to powder position.
In this case,lower powder charges (faster burning) is one thing I would lean towards. Velocity of the powder charge at the muzzle makes a difference in dB's also ya' know. Make use of the breech end of the barrel more. There is that pressure curve thing again. Food for thought.
One other thing. Winchester SP primers are known to be very hot. Might be better if you do not use them.
