this will make it even slower, but to reduce IDL blotches, change IDL IC to 100 (no cache, just to agree with cspear), increase IDL samples to 4096 (or higher) and increase IDL bounces to 16 (or higher).  the latter also allows for decrease in hsv value of hdri. these values must be set in the numeric entry fields, as the d3d sliders maxx out too low. of course, some of these can't be set properly in the default poser render settings dialog box.

ray-trace IC setting is ignored by FFRender when using IDL IC, but nocache is less prone to errors and is reproducible, unlike cache, which is "monte carlo".  nocache reduces blotch size, but samples tend to eliminate blotches.