sinc-L group can do only power of two rate multiples. sinc-short/medium/long don’t have such restriction. This matters when your DAC doesn’t support DSD at multiples of 48k.
No, with Roon you notice some amount of lag between starting playback and you hearing the music. Or in particular if you seek around the tracks. Essentially you have larger buffer between input and output. Otherwise during playback the delay doesn’t have effect, since there’s plenty of delay in any case from the recording even to the playback.
So in practice it matters mostly if you use HQPlayer’s realtime input feature.
v3 is latest update of the modulator with minor tweaks compared to v2. While super/light are new designs.
From simple metrics point of view, all these are extremely good. But there are still audible differences due to how modulators work. It is more like difference emphasis on different aspects. There is no obvious metric which one is “better”.
I think light/super are best I can do at the moment, but if you prefer v2/v3 over those, it is perfectly fine from objective point of view (in particular, any EC modulator is).
So also don’t disregard “light”, it is also very good and I would say better than for example v2. v3 and super are more similar to each other while still being quite different.
It is best to give each a listen on your system, with your DAC and music and decide with one works best for your case.
It wouldn’t help anything…