I hope this is the right place to ask. I'm studying some Scarlatti sonatas for myself to enjoy and discovering some things I might like to ask an expert, or maybe just share my own theories.

Example:

K 148 Bars 46 and 50 have a grace note above the trill, so these would be played as we assume Baroque trills should be. How about the others then? Maybe the other trills should be modern style (not starting note above)?

K 170 Has the same grace note above on some trills, the others maybe not?

A similar question, in K 531 bars 83 & 84 they seem like they might flow better not starting on the note above, from my Spanish guitar that I know.

K 466 Bar 7's grace note is in brackets, optional? Trills in bars 28 & 31 are in brackets, why? Bar 12's grace note is a quarter note! Hold it longer? Then bar 7's is in brackets, maybe play it before the beat? This score has many varieties of brackets around things.

Any idea of a discussion forum where people might have answers? Thanks very much in advance.