This method will absolutely work and was invented about 30 years ago by the patriarch of homebrewing Charlie Papazian. Coined the Zap-pap lauter tun.
Be informed, there are other cost effective ways to make a better mash tun. Almost any cooler, a length of stainless braid and some tubing will likely work better.
I believe 3/32 is the size you need, problem is you need a thousand or so?? A braid is 5 bucks??
No offense...but this is kinda like wanting to write with a cut feather quill dipped in ink. But I guess that's how they did the Declaration of Independance. Wrap the tun w/ some blankets to maintain heat during the mash and you could probably brew some fine beer.
Good luck and have fun...pretty funny...did you have any idea that you were actually reinventing the wheel.
Mike