Digital BW, The Print

I have several questions regarding the workflow for QTRgui using WinXP
and PhotoShop. Here is what I do now. Please advise if this can be
improved.
1. When opening a b&w file in PS I convert to QTR-Gray Lab space from
my default Dot Gain 20%. I use Dot Gain 20% because I don't see a
choice of QTR-Gray Lab in Color Settings.
2. After finishing editing I then convert to QTR-Gray Matte Paper or
Gray Photo Paper depending on whether I am printing to matte paper or
glossy paper. I convert vs apply because the Win version requires me
to save the file before exporting it to QTR.
3. I then jump to QTR, fill out the form and print. So far my prints
look good but can I do better?
4. One problem I see is constantly changing back and forth between
gray lab and Gray Paper. Does this degrade the file? Is there a way to
set the default color setting as Gray Lab? Should I do so?

Thanks,
Chuck