Not so good news there.
I personally haven't had any problems with the HUD dials (but I'm using the Highres_Dark_Hud_Dials mod which might mask the problem), or any other signs of instability. TMO 2.1 + RSRDC seems to run very smooth up to 4000X TC.
So, I've just created a fresh SH4 install with nothing but TMO 2.1 and RSRDC_TMO_V502 + RSRDC patch 1 installed, with the intent of doing some play-testing.
I'll start a separate thread for that.