The results will be interesting. If I might make a suggestion, though.

When I sorting out loads in my Muzzle Loading DR, I found shooting both barrels onto a single target made for a difficult time in actually 'seeing' what I was accomplishing with load changes.

I then resorted, from a suggestion here on Nitroexpress, to fire multiple shots from each barrel onto that barrel's own target. After firing 3 to 5 shots of a single load from each barrel onto a separate target, then transposing those shots onto a white sheet of paper, red dot for right (starboard) barrel, blue dot for left (port) showed MUCH more easily how each barrel was actually shooting, relative to an aiming point, rather than looking at ragged holes with labeling on a multicoloured ie: black/white/ or red/white background.

I'd set up both targets side by side, then shoot the left barrel at the left target, and right barrel at the right target, 3 to 5 shots from each barrel, one load - for group as well as group placing.

Then, I'd place each target over a single white sheet of paper, marking the aiming point with a black dot or circle, then red right or blue dot for the that colour's barrel.

That system worked VERY well for me.

After finding a load that gave the regulation I wanted, I then shot both barrels with that load onto a single target.

Shooting multiple loads onto a single target with both barrels, I find rather confusing for my old muddled brain.