Thanks for your responses.
Ed, I'm printing out everything you wrote. Today, you're my hero. I have been well pleased with my medium format work to date, but need/want to know so much more. With fineart nudes and portraits my main focus, I think the 120mm macro would suit me best, but the extension route will better suit my wallet... for now. I'll upload my work, as soon as I can figure out how.

Cheers All!