What size bead do I need for weld-on #16 on acrylic joints?

[cherubfish pair]

What size bead do I need for weld-on #16 on acrylic joints?
I have a hypodermic-like applicator. Should I use it?

And should I prep joints with 60 grit sandpaper? If so, how?

 

[melev]

If you are applying it in the joint itself to act like a fillet, you want the bead to be steady and very fine. #16 tends to shrink about 33% as it cures, and can suck in or create airpockets as it does so.

My first sump, I used #16 to bond all the pieces to each other. It was messy, but worked. Using too much will just create craters in the acrylic material.

I did scrape the edges to get them as smooth as possible, using a utility knife razor blade, held on edge. I dragged it along each edge keeping the blade perpendicular to the material.