Perhaps i can help a bit more, i have a very similar set still in use, its a superbly built outfit. Using modern servos is no problem, just swap the leads into the plugs round, it only takes a couple of minutes per servo.
Anyone building or planing a submarine should snap this up, or anyone not fussed about having the latest gear but likes quality stuff. The only likely issue will be the old rechargeable batteries in the tx, these are very easy to change if you can solder.
Charles.