I want to start using extension tubes along with a Tamron 1.4x converter. The tubes, by Kenko (Uniplus), are 12 and 25mm.
What do I put on the master lens first; the 1.4x then the tube(s) then attach to the camera body or the other way around? I previously knew this but at 69, my memory slips me.
1.4x TC, then extension tube, then body. Consider the TC as part of the lens. You will probably get better answers to this question if you post it in the Pro forum, or the Macro forum. The Buy&Sell forum is mainly just a big swap meet.
There is a good book by Canon out there that explains macro photography and the use of extension tubes with teleconverters on different lenses. It teaches you pretty much everything you need to know about macro photography.
It's called 'Close-Up & Macro Photography' and it is part of the Canon Workshop Series, edited by Jack Clark and George Lepp.
It's pretty much a tell-all book including how to calculate total magnification, field of view and working distances. It's wonderful, but I'm not sure if it is still available.
In case it helps, it says Canon CODE NO. 9-01700 ($18 USD)
I busted it out and looked for an answer to your question about 'order' of the equipment.
Quoting the book (using 300mm f/4L + 1.4x Extender + Extension Tube EF 25 + 1n)
' Install Extender EF 1.4x between the lens and EOS camera body. Extension Tube EF 25 can go on either side of the extender, but the most useful range of close-up image scales is produced when the Extension Tube is on the back of the lens and the extender is on the camera body.
However, when set up in this configuration, the maximum aperture read-out on the camera will still reigster at f/4.0 in spite of the fact that the Extender EF 1.4x is reducing image brightness by one full stop.
If you are using the camera's metering system to determine exposure, this will not cause any exposure errors. But if you are manually determinning exposure, you must factor in that one-stop light loss and increase the exposure by that amount.'
Some other interesting setups they use in the book are,
Multiflash brackets & Ring flash setups
70-200mm f/2.8 L + 500D Close-Up Lens + Extender 2x
EF 100mm f/2.8 + Extension Tube 25 + Extender 2x
EF 28-105mm f/3.5-4.5 + Close-Up Lens 250D + Extension Tube 25
EF 20mm f/2.8 + Extension Tube 12
TS-E 24mm f/3.5L + Extension Tube 12
TS-E 45mm f/3.5L + Extension Tube 12
TS-E 90mm f/2.8 + Extender 2x
Use of the Canon AutoBellows
Plus many other setups, calculation tables, and explanations of how things work technically speaking. It's a very intriguing workbook.