I'm sure I must be one of the last to have discovered this, but pass it along non the less... ;_0... it sure helps to clarify the issues with pictures...

http://www.pacificrimcamera.com/pp/graflex/backs.htm

Like nearly everything posted on the Internet, the Pacific Rim piece has errors. It missed "hybrid" Graflex 2x3 roll holders that can be used on Graflex (as in the SLR) and Graflok backs. Here http://www.cameraeccentric.com/html/info/graflex_1.html is an advertisement that explains them. They weren't made for long, but they exist. I have one, asked about it here and someone, probably Charles Monday, directed my attention to the ad.

The Pacific Rim piece didn't say that that film carriers or inserts or whatever you want to call them interchange freely between shells of all vintages. I've see knob wind inserts in RH shells, lever wind inserts in older shells marked Graphic and without pin rollers. It also didn't point out that there are transition shells -- marked Graphic, not RH, delivered with knob wind inserts, but with pin rollers. And it didn't point out that shells with pin rollers have gates around 4 mm shorter than shells without pin rollers.

Dan it's nice to have someone like yourself that is very knowledgeable about the different items for the different speeds... it helps clarify for those who want to get, or looking into new items for the camera they have.

Thank you..

Other than those minor/detailed omissions, it is a very nice tutorial for anyone looking for an overview.

Another good source for illustrated Graphic/Graflex info is Jo Lommen's site, e.g. his explanation of the different backs and film holders:
http://lommen9.home.xs4all.nl/holders/
I'm sure Jo Lommen made some mistakes too, but the clear photographs on his site have been a big help to me.