Welcome Kiaser!
Wholly cow, that is a lot of work and expense to get a hydraulic clutch. Any particular reason you didn't just use off the shelf 85-91 square body GM truck hydraulic clutch bits and pieces? The nice thing about using off the shelf GM stuff is if there is failure on the trail you can pretty much walk into any dime store parts store and get a new widget. You can't do that with exotic aftermarket stuff plus internal slave cylinders are habitual about leaking where you need to remove the entire trans to deal with it.
I would imagine there will be a lot of adjusting the m/c rod to get the right throw on it. Good luck! That is going to be a PITA. Maybe someone that deals with race cars could give you guidance on that. My recommendation would have been not to use an aftermarket system in the first place. But I got to tell you, I love the reservoir system with your Titlon setup. I've never see that before. I just looked up the Tilton part numbers and will be ordering the reservoir bits to replace my factory GM tiny reservoir for added capacity.
I was noticing it looks like you need to reinforce your firewall at the master cylinder yet still. As you step on the clutch the firewall will flex in and out like an oil can affect, which in time will result in fatigue cracking on the firewall. This flexing can be so slight you may not even notice it but it will be there. On the hydraulic clutch rigs GM ran two rods from the actual clutch pedal bracket to the m/c where the rods actually became the studs for the m/c to bolt to. That design ties the m/c directly to the clutch pedal with no possibility for firewall flex.
I'm going to use your Tilton idea to upgrade the stock reservoir on my 85 to 91 design in my '78 K10 & '89 Suburban. The stock reservoir is way too small.
It's too late now but you could have used this $40 Advance Adapters bracket (pn 715535) to bolt a stock 85-91 slave on a non-hydro bell then used factory GM slave, master and hose to plumb it. They work great and replacement parts can be found just about anywhere.
This is how the AA bracket looks mounted up. The nice thing is if the slave leaks, it is easy to service and it doesn't drench your clutch and pressure plate in the meantime.
As you probably know, there are differences in pedal assemblies from mechanical to hydro clutch. Here you can see the mechanical pedal box on the right and the hydro on the left. Those two rods on the hydro pedal have studs on the end where the master bolts. The problem is these hydro pedal boxes are getting harder and harder to find for square body trucks. Again, the hydro pedals can be found in 85-91 square body truck, K5's and Burbs. Using a stock hydro pedal assembly would take the guess work out of figuring out the pedal to rod geometry for proper m/c operation.
You can see here from the back side how the rods with studs support the m/c.
Good luck with your project. I have a stinking suspension you're going to be fiddling with this for a long time to make it work right. Personally, I avoid as many exotic aftermarket parts as possible in my powertrain just to keep it simple and make it easy sourcing replacement parts if something goes wrong while traveling around the back country of the Southwest. A stock stock GM slave is easy to comeby even in the middle of nowhere Utah backcountry but a racecar slave....nada.