Before I get into this I want to let you know my Vixen Porta mount is one of the original ones. So I can't guarantee this works for the Porta II, but I would guess probably.
So I got a new scope. A 6 inch F4 Newtonian I've using for night vision. While I like the scope, the bottom of the scope was hitting my tripod legs. And right now many great night vision targets are at zenith.
Unfortunately the official vixen extension is $200 and it's hard to say if I could use it as is. So I went to lowes with a mission to find something that would work.
Below are some pictures. Basically 3 bolts from their specialty bolts drawers. And a 2 inch PVC pipe. It'd be nice if it didn't have the 3/4 inlet...but it doesn't affect using the scope with it. And not having to make my own 4 inch PVC pipe is good with me.
I'll try it under the stars tonight...but it's very solid and I suspect it will be fine.