I'm impressed you managed to fit that much work in with all of the other life events. Nice job!
I was fortunate to have a spare 26-spline input shaft for clutch-disc alignment on the install, so that made it the easiest trans to slide in in my life. I recommend using a spare input shaft if you can get your hands on one. No trans jack for me, so I also needed a buddy for install to help... Don't want to have a hiccup without an extra set of hands there to deal with things. Plus, it's a wee bit harder to muscle than the wimpy T5s, lol...
Quick question: I was under the impression that you're installing a twin-disk clutch for the first time. Did you check the depth on the T/O bearing collar/sleeve/retainer/ma-jiggy versus the twin-disk? I screwed that up the first time and the result was a twin disk that would not fully disengage, no matter what. The T/O collar pushed too far in and pressed into the clutch disc. Started off with minimal contact, presumably pushed very slightly into the PP, and seemed to disengage, but it was heating things up and the problem worsened over time. It also was probably why my twin disk failed prematurely warping the rear clutch disc if I remember right. Fortunately McLeod rebuilt it for me under warranty. In the end, the trick was to get a 1/4" spacer that QuickTime sells.... believe it's part #RM-199. I believe another solution might be just to trim the collar (T/O bearing retainer) by the same amount. Perhaps that'd be better because it'd still put the input shaft just as far into the pilot. In any case, I wanted to bring that to your attention for your consideration so you don't go through the same trouble I did... just in case. At a minimum, I recommend specifically checking this to make sure you have enough clearance. I could try to find my old notes about the proper depth, but it might be different on your Magnum.
Frankly, with the ass-pain that the hydraulic T/O sounds like it was, it makes me glad I stayed with the cable & fork in all of mine. I have no regrets on the turbo cars as the exhaust cleared perfectly to the passenger side & everything bolted right in like it was meant to be there. On Black Jack, with the driver's header in the way, well, I just don't take that car as seriously. So, I didn't mind denting the
BBK Header, shortening the fork, & drilling the housing to give the cable a straight shot. Shortening the clutch fork would have been a PITA for me, but a fella down the road cut it and put a beautiful weld on it for $40. Drilling the pricey bellhousing sucked, but I was fortunate, at least, to find one used & paid $650 on the marketplace for it, which still seems ridiculous to me. Can't believe they get away with what they charge for 'em, new. Too bad McLeod & Lakewood stopped making compatible housings & adapter plates for 'em.
It sure is/was a lot to go through for us, but I've been enjoying mine now since the install in February. Before, 4.10s were the perfect strip gear for Black Jack's basic GT40X/E-cam/GT40 intake combo, but since Black Jack went from street stripper to street cruiser, the 4.10s were just too short for the street -- it'd turn 3k RPM on the highway. I drove to foxtoberfest last year with ear plugs in, lol. With the T56, though, they're perfect! It just doesn't act like it has 4.10s, anymore. The tall 0.5:1 6th gear ratio makes it cruise on hwys like a T5 would with 3.08s... night & day! More importantly, you and & I have got a good foundation now, to swap on sticky tires, hit it with forced induction, and still have a drivetrain that'll hold up, while enjoying the benefits of an extra gear. The juice is worth the squeeze, my friend. Check the market place... Foxes with TKOs are everywhere. T56s are hard to find & pricey... usually done with engine swaps and no Climate controls.
Alright, I'll stop the novel. You're doing well, man. Keep it up!