Picking the glass up tonight - the two pieces came to $17.11, not bad!
Took a look around for knurling tools...very expensive/hard to find. I think I'll move more in a 'hex-head' thumbscrew for a few reasons.
First, completely round would mean zero-grip if any kind of algae or film formed on the surface.
Second, knurling or a slot pattern would fill with aforementioned algae/film and require occasional cleaning.
Third, a hex shape gives enough grip without looking ridiculous, and is relatively easy to make.
I plan to leave a 'shoulder' on the threaded rod portion to fit snugly into the drip tray itself. The top end of the shoulder will then be cemented (E-6000 adhesive) into the 'top/nut' plexi piece.
Next tasks:- Finish MTS process. (let dry out; first round mesh sift; second mesh sift; store in tub)
- Install overflow box. (prepare jig; measure/mark; initial silicone; glass placement; final silicone; tape)
- Mark out drill points on 50G. (measure/mark)
- Fabricate drip plate thumbscrews. (thread plastic pieces; cut top portions; assemble)
- Fabricate drip plate. (trim/drill/tap drip plate rests; measure/mark/cut drip plate; measure/mark/drill press drip holes; test; enlarge if necessary)
Drip plate
For the drip tray hole sizing, I will start at 1/16" and test. Once the initial holes have been drilled on the drill press, I can re-size them using the hand driver quickly enough. I think the idea is to have as many holes as possible while keeping enough standing water to allow the drip tray to 'drip' from every hole. I am sure there is fancy maths that can be done to calculate the exact hole size off the bat, but I didn't do that well at math (probably for lack of trying) and this is DIY, not mass production. If it takes 1-2 re-sizings, that's fine. Probably less extra time involved than the calculations.
Overflow box
I had thought about installing the overflow box right away (more time to cure, good visual prior to drilling), but decided against it - too much could go wrong. Also, I might discover that the 5" depth I've specified is too deep and need the glass re-cut to fit. Finally, if I have to drill for the returns, much easier to do that out of the tank.
Edit: This guy has a great overview of his BeanAnimal/coast-to-coast system:
http://www.glassreef.com/basics_index.htm