That’s about all there is to it. I would suggest that rather than cutting up an existing cable, you just order the correct connector and either solder the tally cables to the pins or but a connector that you insert the pins into. Both are inexpensive and easy to do. Or you could use a pre-made 25 pin cable that terminates on a breakout board. With that you can just attach the tally cables directly to the board. Since all of your equipment is Sony, it should be pretty straight forward.
E=MC2+/-2db