What is the correct KOH base amount, there seems to be a bit of debate in the various threads? I'm using 90% pure.

The correct base amount for 90% KOH would be 7.8g./L.

I't's easier to use 8g./L.  KOH is more forgiving than NAOH if you over shoot the amount.

Bob

It seems to work better at 9 g/liter actually. 

Many thanks Mark & Bob - much appreciated. I guess that explains why I get a good deal of precipitate when doing the 3/27 test, I used 5.6g/l which I think I got from journeytoforever. Is it possible to reprocess this batch to get a more complete reaction?

I used to use 7 grams before I was using the 3/27 test.  I had to increase it to 8.5 grams to pass 3/27, using approximately the same amount of methanol (22%).