Teeth for the overflow?
 

What would I use to make the teeth for the overflow?. It will be plexi-glass ordered from Industrial Plastics. Would a drill be fine? or am I going to need a Dremel? Or should I try and get Industrial Plastics do it for me?.

You can do it yourself but if you break a tooth it's your problem.

It's worth it for you, to them to do it. They will most likely use a table router with a jig so you get a clean professional looking overflow.
Just my 2 bits

I used a router to do mine. If I didnt have my router then I may have braved it with a dremel but the router is much better.

Cool thanks guys. I think I'll see what they want to charge me for it Vs. doing it myself.