This really should not be that bad, just tedius. Start by drawing out a large likeness of the fuse panel so you can make notes. Remove all fuses, flashers, etc
REALIZE the following: Most fuses are going to be fed "common" from either:
1...full time hot source or
2...Accessory from key switch or
3....Ignition "run" or
One or two fuses may be isolated AKA dedicated wire to and from the fuse. An example of this in your old box is the small "inst" fuse which feeds the dimmer controlled panel lights. It is powered from a tan wire coming from the headlight switch dimmer, goes TO the inst fuse, and then the output of that fuse feeds off to all dash dimmer controlled lighting.
You can "get a clue" by the fuse labels. HEATER fuse for example, is going to be fed by the ACCESSORY output of the key, rather than "full time hot" or "ignition run." Once you have those wires identified, one, likely the larger is PROBABLY the input from the accessory from the key. Now take THAT identifed "probable" wire and probe other "Likely" fuses such as AC. If one side of AC also goes to to that wire, then that wire IS your "ACCESSORY" input to the fuse panel. AGAIN you are doing this with FUSES REMOVED. This prevents confusing backfeed
You can see bottom row, 3rd from left seems to be "stop lamps." This is likely fed from the "full time hot" input so find what wires both sides go to then see if you can find other likely suspects that are common with one of the wires, and this is going to be your "hot" feed in.
Top row far right seems to be "INST lamps" so this is likely the isolated one wire in/ one wire out just like your 65. "Suspect" that the colors may be the same, tan and orange.
Top row second from left seems to be "RADIO" so one of those two terminals is likely your ACC feed
See? EASY!!