Any suggestions on an affordable water activity meter? They all seem quite pricey.

Hello
Starting to experiment with meat sticks and want some help to ensure i make the right purchases.

My plan:
Use chuck flap and beef fat farce
Slim Jim size stick end result

A Curveball:
I want to try to execute this out of a Rational Oven

Basically:
What size casing would i need and accompanied stuffer tube

What chemicals would i need to ensure a solid end result

Thanks for any and all help
Please let me know if you’d like any more information!