I'm going to post the below formula on behalf of Seymour who made it up on the spot while round mine last summer. It really is the best blue formula around and I have tested the veline one, some of the ones of pyroguide and "pyro science" blue (which is better than others too but not quite as good as...)
Seymour's KP blue
KP – 58
Lactose – 15
Parlon – 9
CuO – 8
Red gum – 4
Sulphur – 3
Mgal – 3
I would like to try this formula out, when you say KP are you referring to Shimizu's formula? Can you just use Potassium Perchlorate on its own or will this affect the colour?