Didn't datsville have layers, maybe hide (ghost) one of the bigger ones while working on placing the minifigs.
I also thought up a shorter method you could try
click on the minifig in model B.
double click on any LDraw part in the part bin to replace the minifig.
open model C in nested and select the part just used (at where the minifig used to be).
double click on the minifig in the part bin overview group.
This way you have minimal interaction and thus fps issues.
I also thought up a shorter method you could try
click on the minifig in model B.
double click on any LDraw part in the part bin to replace the minifig.
open model C in nested and select the part just used (at where the minifig used to be).
double click on the minifig in the part bin overview group.
This way you have minimal interaction and thus fps issues.