You're welcome. 
But don't expect too much from that 4 dollar lens, it's by far not as sharp as a low powered microscope objective. I own several bellows, the most expensive one, a Canon FD Auto bellows was $ 90.- A big bellows only usable in a studio setup. I also own an (older) novoflex bellows which is *much* smaller but can extend almost as much as the FD one. This one is for use in the field. Finally I also own an Olympus telescopic auto tube. Basically a helicoid ( works like a zoom lens; turn to change length) but these are rather expensive. I got mine as part of a batch and I'm currently selling the other items from that batch. With a bit of luck that will set the balance for the auto scope to zero.
But it doesn't really matter what bellows you get. Preferably get a sturdy looking one and preferably one that has an indepent positioning system for both the back and the front of the belllows. The latter can prove to be very usefull but is not a must have AFAIK.
When it comes to microscope lenses, again it doesn't really matter much up to 10x. The cheapest ones ( which are still very good) are the finite ones, for use with a tube ( = in our case a bellows). They have a reading on the barrel like 160/- or 160/0.17.
The 160 stands for the needed tube length and the - and 0.17 indicates the thickness of the coverglass that need to be used. Up to 10x the image quality will not degrade noticably if you however do not use a coverglass on such an objective. Note: Tube length is the length from the shoulder of the objective (the place where the screw threads meet the objective) to the sensor(!) minus 10mm. An EOS has a flange-focal distance of 44 mm, so the bellows should extend 160 - 44 -10 = 106 mm. This is of course exluding the thickness of possibly used adapter rings.
If you change this distance, the objective will still work (either more or less magnification) but performance may/will drop considerably.
Finally you will need to have a mechanism that allows you to take very small distance increments to the subject photographed. Microscope objectives have a *very* small DOF ( much smaller then any dedicated macro lens or any setup with reversed and stacked lenses). Stacking is a necessity when using these objectives.
I use several mechanisms but the cheapest solution, which still works like a charm, is a linear stage with a micrometer as an actuator ( such as this ebay item: 160555413726).I have mounted mine in between my camera and my tripod using plates so it can easily be clicked on and off. I paid only 24 US dollar for mine so they can be had a lot cheaper then the one I pointed to.
Once all is setup it is just a matter of taking a pic, adjusting the micrometer and take the next pic.
