Homebrew PCBs

Hello!
  I just made my 1st Photo PCB lasts night.  Turned out great!  Well,
actually I did make some PhotoPCBs about 15 years ago, but they were
very crude.  First I did a test exposure, to see how long to expose
with my light source.  I uncovered another 1/2" of the PCB every 30
seconds.  Turns out it needed at least 7 minutes, and 13 minutes
started to be too long.  Thanks to reading about other people's
experience, I didn't have any troubles.

And now for a few questions.  At what point does the PCB stop being
sensitive to light?  When I put it in the developer?  After it's
developed?

I have access to some CNC equipment (Taig with a
www.CNCOnABudget.com's 30krpm spindle).  Lining up the PCB to be
square w/ the axis is difficult.  Does anyone drill the PCB before
they expose it, or before they do the tonor transfer step?  I'm
wondering how this might work.

I use Eagle to layout my PCBs.  I was researching their forums, only
found questions on how to do what I don't want done.  I would like my
pads to be filled in.  For some reason, using my Epson injet printer,
with Epson ink and Epson transparancies, the rings around my resistor
pads are too thin.  So I'd like to fill them in.  I can't figure out
how to do this by doing a File->Print.  In the CAM section, I think if
I output to device PS or EPS (post script printers?) there is a
checkbox for filling in pads or not, but I don't think my epson injet
accepst postscript files.  Any suggestions?

Also, what to transparancy users do when they have a small board to
print, and don't want to waste an entire expensive transparancy?  Cut
out the size they need and tape it to a piece of paper?  This is what
I use to do when I used DynaArt's toner transfer paper.  Have not
tried this yet, but I will next time.

Thanks for your help,

- Steven Ciciora