Looks like that setup works pretty well. I haven't had good luck with teleconvertors, I have 3 or 4 but usually I find they degrade image quality so I use them very rarely.
I've gotten a few new ones lately, using the binocular lens rig, my favorite for macros so far.
This one is very small, the hoverfly lit just as I was focusing so he got into the picture too. The hoverfly is under 1/2 inch long, the whole cluster could hide behind a dime. I'll have to try and look these up again, I think I finally found them last year but not sure.
Another very small flower, the whole cluster is about the size of my thumb, individual flowers about 1/4 inch wide. Unidentified.
White clover after a good coating of dewdrops.
All with SMC Pentax A 50mm and binocular lens attachment. Flash was used for the clover, ambient light for the others. Flash is the only way I can get a shot at f16 that early in the morning...the others are at f8.