Homebrew PCBs

Here's what I will be using.

http://img218.imageshack.us/img218/4043/box19ks.jpg

it is not finished yet, but still. I can't change the distance between
tubes and glass once finished, so I'll have a try.
the two tubes will be separated a about 2 cm from each other, and both
of them at 7-8 cm from the PCB. Each one is 6W, so maybe they are not
too close.. I hope! :)

On the other hand, I will put a reflecting surface below the tubes,
but I did not plan to close the sides of the "box". As it is quite
close, I hope no reflector is needed, as I find no easy way of adding
them.
I'll try 5 minutes, then 8 minutes, with 2 different little boards,
and see which one comes out better.

I will be using metasilicate (I hope this is how it's called in
English) instead of NaOH for developing. Do you guys know if I can use
the solution several times, or have to throw away each time??
About 2 minutes for developing would be a good starting point??

thanks for your help!