Measuring the SG and the TA of a fresh red must had always given me
problems. I presume that this is because the juice that floating on
the top isn't representative of the entire batch. I also imagine that
my SG readings are artifactually high due to suspended solids.

Does this make sense? Can I rely on a refractometer reading (assuming
that the must hasn't begun fermenting) and discount the initial SG
readings?

Also, an experienced winemaker told me that he ALWAYS pretreats his
fresh musts with sulfite before pitching his yeast a day later. He
says that it helps knock off the native yeasts and that he has more
control of the outcome. Is this a common practice? I tried it and
ultimately had no problem whatsoever with my MLF, so it seems like a
good idea.

Lee