I've never tried it with a 1st reaction, but it does work if you have to do a small last reaction (2nd or 3rd) there is always excess methanol present so just adding KOH does work. I've done it many times with amounts around 50gms.
Two things to remember;
1 make sure your pump will take the sizes of flakes you put in. The Panther didn't like it but the 120 doesn't mind.
2 It's got to be hot and mixed for a good while, otherwise when the processor is empty some flakes are still there.
During my glycerol enhancing experiments someone asked why I didn't just add the KOH to the glycerol, so I tried it. No way on gods earth will koh dissolve in glycerol!