Nota - very fair points, and ones which I need to mull over ahead of responding. I totally agree about the cost increase being due to needing to solve the Yr3 problem and not due to the needs of the project itself!
In terms of the RN carrier strength in the 60s, yes the mid 60s was a good time to be in the RN in theory, and I would personally regard it as the time when the RN was at its most effective. We'd cleaned out most of the war time ships, got some great RFAs into service, were seeing some first rate escorts and SSKs (and a few SSNs) come into play, and still had a hugely credible global influence. In my mind, the period up until the decision to go west of suez will be the time that the RN was at its post war peak.
That said, if you look at it, Eagle wasnt back in service till 64 (carrying 30 Jets), by which point Centaur was down to just Sea Vixens (9 of them) and Hermes was carriyng about 20 jets. I cant find figures for Vic. Even so, we're still only looking at a full on seagoing force of about 60 jets, with at least one CV in Singapore, and the rest in the UK or elsewhere. Some great aircraft were embarked, but things like Sea Hawks and Scimitars were not great designs, with no radars and limited capability, even compared to their peers.
As for the Invincible CAG - my understanding was that when she was running 16 FW jets, they moved the pingers onto the escorting RFA, usually one of the AORs, who were designed to run them. Essentially spreading the airwing over 2 hulls - not perfect, but still representing a very capable package of assets. This meant we were looking at usually a 24-26 strong airwing over the 2 hulls (16 harriers, 4-6 Merlins, 3 Baggers and a lynx or old SK). Compared to any post war UK carrier air group this is just as capable, if not far more so when you consider what the airfames could do. I still maintain that the late 90s carriers were just as, if not far more, capable than their predecessors of the early 60s.