I played NL200 HU for two months after being unable to break into MSNL 6-max games and had several 10 buy in, two 15 buy in and one 17 buy in downswing over the course of about 50k hands. But I still managed to sustain 13ptbb win rate over this sample (/subtle brag) and made some crazy money like your experiencing, but just be prepared for the swings the other way.
HU will improve your game HEAPS though. Trust me. You'll learn how to THINK. How to bluff and play with wide ranges and you get into some crazy deep stacked situations in aggro matches which is an invaluable experience and advantage to have when you go back to 6-max. If you stick out for 30k+ hands HU you will come back and crush 6-max. But be prepared for crazy swings, even at SSNL HU.
Nice brag though

I do miss the days where you absolutely soul crush opponents for 10+ BIs
