A while ago, I asked what was the correct way of changing the font used to set operator names. I stabilized at:
\DeclareSymbolFont{sfoperators}{OT1}{cmss}{m}{n}
\DeclareSymbolFontAlphabet{\mathsf}{sfoperators}
\makeatletter
\def\operator@font{\mathgroup\symsfoperators}
\makeatother
Now, the peculiar combination of fonts I am using (Bookman at 11pts, standard cmss) results in the operator names being set in letters which are too small:

Can I change the fontsize used here?

mathastextpackage for getting math in Bookman, but I'm afraid that the results won't be very good in all cases. – egreg Jun 22 '12 at 23:21