Check out this thread: https://www.catalina36.org/forum/technical-discussion/revamping-control-line-scheme    
In comment # 9, I posted a very detailed set of photos of the control line scheme we installed on our former '85 C36 Mk1; it worked quite well for us.

The layout we came up with evolved from ideas copied from Tom Soko's former C36 (you can find his writeups somewhere on the site), with some changes.   The underlying premise was that we wanted to have all the sail controls brought to the cockpit, including the ability to reef the main without having to go forward. 

The first step in this process was the installation of the "Dutchman" system on our main, at the recommendation of of sail loft, which keeps the main from blowing all over the place when its been lowered (which also required putting into service a previously unused masthead block so that we could adjust the topping lift that way rather than at the boom end).   When we first got that boat, the possibility of running the halyards aft existed, but we found that the friction induced by the turning blocks on the cabin roof  rendered it too finicky to use, so instead we continued to raise and douse the sails at the mast.  The solution was to relocate the turning blocks as far aft as possible, to lower the friction by making the turning angles significant;y shallower (and replace all the sheaves with high-quality ball bearing ones from Garhauer).     That seemed to cure the issue.       

We had to relocate the cabin-top winches inboard (on our boat, in their original position the dodger interfered such that we couldn't do a 360-degree rotation).   Reinstalling these, as well as the various turning blocks and line clutches, involved adding a lot of backing plates on the inside, of course, which (if I recall correctly) were thick (perhaps 1/4") aluminum plates.   I looked but I don't seem to have any photos of what the backing plates looked like, I'm afraid.  It did make the interior ceiling look a bit industrial!

And, as you can see, we replaced the original traveller (which essentially could only be adjusted when we were well off the wind) with a Garhauer, which was modified by Garhauer to lead the lines and turning blocks as in the photo (this was in consultation with the late Guido Gargiulo - the "Gar" of Garhauer - to our specs).  BTW, Garhauer is great to deal with -- they are a small company that made the hardware on our Catalinas, and their gear is top notch.     

To answer your other question -- and mind you, we sold that boat in the fall of 2021, but we did use the system  for 8 seasons --  I don't think there's anything that in retrospect I would have changed, except maybe to keep the jib halyard at the mast (with a dedicated winch), since we rarely had need to adjust it once we'd bent on the jib for the season (and someone had to be up on deck anyway when rasing or dousing the jib anyway).  Yes, in theory we should have slacked the jib halyard at the end of the day's sailing, but in practice we didn't) so all that halyard coiled up in the cockpit was just more spaghetti to deal with.  But in general, we really liked the system; in conjunction with the Tides sailtrack and the Dutchman system, we were able to easily reef (or shake out reefs) while underway, and being able to do so easily meant that we sailed more comfortably and safely (as opposed to waiting until things became too crappy before relenting and putting in a reef or two).   In hindsight, it was among the best improvements we made on that boat (along with the swim platform).