The quality of percussion conversions often depended on if it was done in town by a gunsmith, or out on the frontier by somebody with a little gun knowledge. Or, not.
I personally enjoy making conversion guns, because to me they just seem more authentic to the times. I usually use copper wire hammered down tight, to plug the extra holes in the plate. I cut the pan off, but usually try to leave the fence in tact. Converting the hammer as shown by some of the others in the forum, really makes the gun look old. A little creative aging lends a lot to the project as well.
Hungry Horse