Yeah refresh my memory you navy types but didn't the 3, or 4, ship gas turbined Kittyhawk class have high pressure steam catapults? And they weren't much bigger then this new Brit class right? And no doubt the technology is much more refined now and miniaturized then when the Kitty was launched.
Actually I thought the Lizzies were being planned in the 40,000 ton class. So what your ending up with is a legitimate supercarrier.
And dont forget that part of the reason you are leaning towards STVOL F-35s is due to the outstanding service of your Harrier force. There are some Plus's going the STVOL route, such as quicker turnarounds, easier operation/safer in high sea states, and reduced cost.
And dont forget. While they will be on Navy ships they will be flown and operated by the RAF. And the RAF has always leaned towards STVOL.
Your going to have to think outside the box a little here. The F-35 is being designed to be probably the least labor intensive fighter aircraft ever produced. Land em, load em, gas em, and fight them. Time and time again with as little down time as technically possible. Even the stealth coating can be touched up with a paint brush. The amount of sorties and firepower the Lizzies will be able to sustain is going to be unprecedented. STVOL requires less deck space, less upkeep, and will be able to sustain combat Ops in the 30% range more then conventional CV F-35 aircraft.
Even better the RAF has tons of experience in STVOL operations, training, technical expertise.
Lizzie battle groups will consist of advanced air warfare DDs, advanced SSNs, very capable amphibious warfare ships, and about every advanced western weapons system you can think of.
But dont look at the STVOL option with such a narrow mind. You buy expensive systems based on the mission you will need them for. You dont buy them just "to keep up with the Yanks".