Hold be back... (smile)
Well, I've never had the opportunity to use your beautiful classic desk but I'll toss in a siderail for ya and tell you to keep that gem and possibly use it in a hybrid setup.
I've been to Pro Tools hell and back and I am now hybrid and Sequoia 11, going on 12 and really happy about this more and more. Pro Tools "HD" has a sound of its own and its not pretty IMHO but that's just me and I'm radical and not normal by any stretch. That doesn't mean its not awesome. PT is a kick ass DAW and I don't blame you for wanting it. Its the industry standard and for good reason, but, its not the best sounding system by any stretch.
I tend to dump things at the time everyone is buying in. Kind of like "sell high buy low" but not because of profit on this one, more like its old news to me and hybrid is merging for good reason.
Since you already have good taste you may want to read a bit more on hybrid before selling it or making big decisions that may take 4 years to figure out what the hell happened lol. . Okay, I'll stop now and enjoy the discussion.
Are you using external pre-amps and other hardware or are you sticking with the turnkey HD system and going plug-ins all the way? Keep in mind, HD is going to be replaced soon enough with something bigger and better so if you are getting the HD I'd wait a bit longer for the real deal there.
Sorry to siderail you but I hope it helps with some clarity.
Welcome to our community!