ston
Well, the HD400 was collected today free of charge (GAK's customer service really is tops, I definitely recommend those guys if you're in the UK) and best of all the Input Level Adjustment window in TH2 Producer is working! :-)

Just curious... what got it working again?
 
As far as Line 6 stuff I only have one experience with their gear and that's my Line6 Duoverb head. From what I understand this was a pretty early release from their company. I bought it to gig with because I had destroyed yet another one of my heads and got it pretty cheap on ebay but it always gacked out at stage volume. No idea why. Just... it would crackle a bit then totally stop responding. It should have been powerful enough to run my cabs but it wasn't so it got relegated to studio duty for which it's pretty darned convenient. Most of the sims on it are pretty cheesy and weak BUT with all the crazy i/o stuff on it it's great for tracking. It has two channels that can be independent or blended into each other (two amps at once basically and I keep them separate, not blended) which can be sent out in stereo through line out or 2 XLR outputs. I use the XLR outs to record two tracks each with a slightly different amp/EQ set up. Then I can pan those in the DAW without phase issues (if I do it right).
 
But the sims are very old tech so anything beyond using the cleaner models doesn't sound very good. I just toss my software sim(s) on the tracks and work that way or if I want to get my old metal sound I put a stompbox in front of the amp head to record the distortion destructively.