I have/had plans to run a high powers game myself, I would have handled it a bit different though.
To me, just handing out more BP's and high avail but following standard rules doesn't seem to fit. An important part of the whole "veteran" thing isn't higher stats and skills, but experience expressed in the form of knowledge and contacts. (A run in Paris/Moskou/Being/Rio huh? Yeah, I've passed through there a'couple'a times. Know some fine eating there and a guy in the suburbs who can get us what gear we need.)
Rules: start with standard rules 400BP characters and play at least one, or maybe two short runs. Just to get the "team" feeling. Maybe have it connected with the actual high powered game you'll run later, have some of the things decided/happening on this run have an impact on the later game (who'd they piss off, befriend, kill or let live).
Then, flash forward a couple of years. Explain what they've done and who they've worked for. Maybe some random rolls deciding who once saved whose butt or who messed up bit time that one time we almost ended up in jail.
Reward: x00 karma and x00.000Y, extra knowledge skill points equal to (highest stat+ logic/intuition) x 2, 3 or 4. Double/triple the amount of points the chars originally spent on contacts. (And of course, they can spend karma too).
The've had plenty of time to ignore the training time rules and met enough people (and had enough time) to get anything up to xx availability (can spend karma on Restricted Gear to increase it).
Possibly some extra (edge?) rolls to decide some new qualities, both good and bad ones. Maybe he became ambidextrous after all that practice, maybe he made an enemy or got a mysterious implant.
Anyhow, that's what I had in mind for my game. This way they'll have been "starters" and know what they came from. They can make up their own history starting from that point too: Why did that contact's loyalty increase? How'd you get rid of that Addiction? When'd you learn about fine wines?
Also, this way, who they were has a larger impact on who they've become. That street sam full of second hand cyberware will have to decide what to replace and what not to... Immediately starting as a "pro" means he'll never even have bought those "obsolete" pieces, but let's face it, noone just starts with betaware implants!
And instead of Mr. Mage running around with his pocket full of Force 6 foci, he'll have some lower-rating things that might still be useful and have a history.