Thanks for answering.
Tushingham still do a 490 45% mast.
I was using it with an older 8.6m Tush freeride sail for around 4 hours at the weekend...and you'r right its heavy!
At this size they do get you up and going in light wind, and are ok as long as you don't drop them in the drink, then they start to get very heavy once you've pulled them up a few times. (not water starting yet).
I was just wondering what was the point where the weight of a rig could overcome its size benefits.
I'm shortly going to get a 460 75% freewave for use with a 7m Tush freeride. I'm only 70kg so maybe this will be the better option for me until I have the water starts cracked.