@SciMan Would you be able to share the "CFG suite" for your engorged fixed radiators? I would also love to create large radiators based on the HeatControl parts, but it's definitely a bit more complex than tweaking tanks. My current understanding is that we edit:
SystemHeat patch for HeatControl parts
Add B9 MOdule Manager section with subtypes for desired part sub-types.
I thought I did this well enough, but it seems actually that I cannot just *edit* the patch, but need to create a new one...? I am not sure.