I am in the same boat as Bruce as a Jack of All Trades...Master of None when it comes to glass. I collected U.S. glass animals for over 20 years & picked a few things to support my collection so I had to develop a knowledge base of U.S. manufacturers. Then I had two kids in college at the same time when eBay started so in 97 I put up a spare pair of Cambridge Scotty bookends & was astonished when they brought 4X what I paid for them so long story short I ended up selling around 150 animals (goodbye collection) by late 99 & a few other things I picked during the years which fully paid for two college educations. So for the last 14 years I started picking up a wide variety of things to sell, especially the last 10 since I retired & even started picking European at times if it was good quality, but my knowledge of European is sadly lacking (thats why I come here). Its pretty much run full circle as during the past year DW & I have sold off 95% of our U.S. collection to other collectors & dealers (and in two mall showcases)as kid's (ages 37 & 40) really didn't want to deal with this after we had gone so pretty much all we have left is European although I still pick good U.S. but it has to be really good.
Roughly 38 years of doing this on the side has been a blast & I have grown to appreciate glass from just about everywhere as long as its real quality & not junk. Salviati? yeah me too...recently sold two perfume urns Ivo ided for me...didn't really want to, but had a Godfather offer from a perfume/vanity collector so they went to someone who would appreciate them.
On cut glass...speaking of the U.S. only, I think the problem has always been attribution to a particular cutting shop/company as it takes years of study with the pattern books since 95% of ABP was not signed to develop any expertise as so many patterns resemble one another & it takes a specifically trained eye to tell who did what. Best stop rambling on now. Ken