Why not put a glass chillum for a mouthpiece!
3/8" silicone tubing for the seal.
Now you're talking! Or as they'd say 'now you're cooking with gas'.......
I like it, but why not go half inch and seal to the OD of the chillum? Or 5/8, 3/4 whatever. That is not add any restriction and make it easier to connect to the chillum.
I'm thinking about a SS tube .570 (or whatever you decide it ideal/available) inch OD and say 1.5 inches long. Chop it off, bevel the ends, polish and clean. Done. Each guy gets a stand, basically a flat, round headed bolt threaded into a base block. A post you can screw up and down to adjust bowl size. To build the stem you'd use the normal snap ring pliers to start a snap ring into one end of the tube. Then push the tube down over the tool to push the ring to the right level and square it. Next, drop a screen in the open other end, start the second ring in and push it home with the dowel (AKA 'stick') part. Like a ramrod. Against the tool, trapping the screen between the rings at the right spot (set by the tool).
You could, of coarse, just use a few different length pegs instead of an adjustable tool, but something solid and pretty that let you adjust to whatever size bowl you want would be kinda cool I think?
A guy could make the parts on one of those table top lathes quite easily and quickly. And a vibrator type tumbler could do the deburr and finish. The rest can come from M/C, USPlastics, and the chillum shop near you. Or import a bunch?
A few hundred bucks could get it going. For what you'd waste on a new vape or rent or something you could buy some tube, a vice, hacksaw, a couple files, snap rings and pliers, and start experimenting. Keep it all in a shoebox. After you get tired of spending so much time filing one to fit, a small additional investment brings the lathe and serious speed and quality gains.
Or you could draw the part(s), or even make samples, and bid them out to either local shops or some offshore shop.
You could easily do a pilot run, or even modest production runs, in your garage or spare room (if there is such a thing.....). With small capital investment. Then 'farm it out' if it got out of hand?
Could be a fun project for a guy that wasn't already busy being retired.......
OF