Allow me to preference this by saying that...I only know Canon!
I use a 180 macro...sometimes, with Kenko extension tubes and sometimes using Canon's 2X teleconverter added into the equation, successfully I might add. There is some shadowing at the corners from the tubes that is easily curable in RAW processors. Needless to say that it is a setup that requires a tripod and manual focusing, I use a tethered scenario with computer controls. Additionally, I would suggest a brace of some kind to aid in lens support due to the length of the long set-up. Something like this...
We all have different types of tripods...right?