I did the 100A mods for those that posted. I didn't see any private message on the subject, so apologies for not seeing this sooner.
Right now I'm working up an HQ-120X in between the move to an apartment and work, but the circuit isn't as condusive as the HQ-100. For this, I'm going to build an external BFO that's remarkably still available from Ten Tec http://www.tentec.com/index.php?id=60
I know it's a terrible thing to do, but there's not a lot of space under the chassis, not neally enough room to mount another tube circuit, and I can use the front panel mounted switch position for the new BFO so that it retains the outward appearence of being original.
May be something you might wish to consider if you don't want to go the route of 100A modifications.