Yes I have several, but they're in aeroplanes so I'm unable to take 'em out at this moment.
Yes the bladder tanks are the same dimensions but have a reduced capasity. I believe the 20oz becomes an 18oz bladder etc. Don't used them, only used them as standard.
Most of the guys, me included have made mods to the aeroplane so they're able to get the 20oz in for 1.40 2-stroke flying, the 16 just not giving enough breathing space unless you like flying the approach on fumes. The 1.40 YS's seem quite happy with the 16... but it's getting close.