I ended up getting the 12oz from him (quality injector and more on fb). Got it yesterday and it’s awesome, only got a chance to play with it a little last night, but it’s very smooth, dual locking pins, dual orings on the plunger, very smooth action. I will say that it had a lot of dust, I assume from manufacturing, in it when I got it, but ran some worm oil through it a few times, cleaning the plunger and tube out each time, and no big deal.
it was around 26 degrees last night, I did have a propane forces air heater going, but the injector heated up quick and stayed hot, most of the time the plug on the inside was less than half an inch thick, even putting 8oz in.
this is the 12 oz next to a 6oz basstackle, not much difference in length and it’s pretty easy to use, so far pretty happy with the purchase!