Feel free to post any questions publicly, unless it is price negotiations, contact info, etc. Otherwise, if it is something others would benefit, I will publicly post anyway as an FAQ.
Here is one that just came in on another forum:
which lens/bellows combination get the highest magnification for macro shooting?
Any lens can do macro. The shorter the focal length, the higher magnification for the same amount of bellows extension. For maximum magnification, while also allowing lens tilts, shifts, and swings, the 4 fold bag bellows is best. The 80mm extension rail gives you the most reach. It is harder to obtain than the 40mm rail. However, with the 40mm, many users will just leave it on, while the 80mm makes the camera quote long, and may get in the way when shooting close. the 40mm is a good 'all-around investment for closer distances, and you just mount it and forget about it. the 80mm is good for those that want maximum magnification. I have both the 40mm and 80mm available, and the 2 fold bag bellows (useful for extreme movements with shorter lenses) and the 4 fold (good for longer lenses and close-ups, however problematic with 65mm and 50mm lenses and movements at infinity.
So, theoretically, most magnification would be with the 50mm lens and 80mm rail combo, but working distance would be small. The 80mm, 100mm , and 135mm are most popular for doing macro. Any of the lenses 80mm and over will provide the best results in macro. If you want super thin DOF and amazing bokeh, than I would go for the 125mm f3.2. If you want deep DOF, go for the 80mm or 135mm f5.6. The 100mm is a middle ground.
Hope you buy something from me!
If you would like more information about macro, formulas, specific performance, and a complete solution figured out for you, I am available for consulting...very reasonably. $50 per half hour, pre-paid via PayPal. Includes access to lens tests. Can save you hundreds in the right / wrong decisions.