"Gary's Chemical Lime company" is Chemical Lime CO...the problem with them is that the lime they carry is a dolomitic (high magnesium) lime. This lime is not really good for fresco. You need to look for high calcium lime.
Margaret Thomson and CHem Lime might help you.
However we at TrueFresco gave up on the idea of finding reliable source for calcium high lime in US - it is just not commercialy justifiable for them to help us (fresco artists). So we bit the bullet and import our stuff from Italy.
Try England and Scotland, Ireland - they have tons of that stuff and even with shipping... getting quick lime there should be cheap.