A damn good dump pouch should be on your list (dump the spent shells in and keep your speed up). You can either get rid of one of your drop leg holsters and replace it with a dump pouch or find a dump pouch that connects to a belt.
http://www.tacticalassaultgearstore.com/dumppouch.aspx
Get a few 40mm shingles:
http://www.sordusa.com/shop/home.php?cat=24 (their send time is pretty quick and shipping is cheap - quality is tops and they're used by Australian SF).
That or a 40mm bandolier:
http://www.cpgear.com/StoreBox/wpac/8016_1.htm
I'd do a combination of both.
I'd honestly ignore the ciras vest and go with a smaller plate carrier or even straight-up molle chest rig. You'll need as much additional weight reduction as possible instead of weighing yourself down with more kit.