Here's my .02 cents. Been loading shotshells since 81. Have 4 MEC 600' s in 20, 16, 12, and 10. One Pacific DL-155 in 16 plus a PW 375 with 12 & 16 tool head.
Use Red Dot powder.
Get a specific charge bar for 3/4 oz lead shot for each gauge and decated use on each loader.
Get a powder bushing for each gauge at the power fps/pressure you desire.
Claybuster will likely be your best bet to find wads for both your 12 & 20 gauge 3/4 oz payloads.
Use a quality hull.
Your best bet on hulls will be Winchester AA red hulls in both gauges.
Your crimp will be a major determining factor in your shotshell performance.
Good loading an have fun.

Last edited by nitroexpress; 01/25/22 07:48 AM.