I'm doing exactly the same thing. Or very similar anyway as I'm fitting a MK4 steering column to a corrado. I have a spare lower column which I got cheap so it's no big deal if it messes up first time.
I'm wanting to have it welded and machined so it looks as oem and works as normal as possible. I left it with my engineer and he said it wouldn't be a problem. I'll hopefully get pics this week sometime if he gets it finished for me. It's a little different to your setup though.
Here's the test column.