In all sincerity, how much weight will you save by going to a lighter gi? 2 or 3 lbs?
For my money I'd cut that little bit of weight, especially if weigh ins are not same day.
Let me rephrase, the ripstop PANTS are totally fine at Gi tournaments, including all IBJJF tournaments. The Jacket varies. The Pan-Ams and Mundials might bitch at you, but Lutador, US Grappling, NAGA, etc... won't.
So let granpa omega simply wear the lighter gi rather worry about whether he needs to drop weight or not. The good news is that I don't have to do a 10 minute match although I've been contemplating moving to the Masters division instead of the seniors.
I own or have worn the following:
My current lightweight 'go to' gi. VERY VERY minimal shrinkage (only because I was trying to shrink it - hot water + dryer - and even then it didn't shrink as much as I wanted). Rip-stop pants are very comfortable with plenty of room to move. Jacket feels like a 500-550g weight weave which is very light. It is lighter than my Vulkan (which weighs in at 3.8lbs for an A4).
Vulkan Pro Light
Very comfortable gi with a fabric that feels soft to begin with (unlike a lot of weaves which feel like they exfoliate your face). Again, VERY VERY minimal shrinkage, if any at all. Pants are not rip-stop; they are a light-weight cotton, maybe 300-400g weight(?). I couldn't shrink it down to my preferred size so it is a backup. A4 weighs 3.8lbs.
This one is probably the thinnest/lightest gi I've worn, but the jacket is rip-stop and of questionable legality in IBJJF and other organizations. I know my coach competed in one at Worlds though. I only mention it because it seems to be where gis will be heading material-wise in the future. The weight chart in the link seems off a bit. I KNOW this gi is lighter than my others.
Gameness Pearl Weave
The one I own is 3 years old and I believe they have changed material weights since then (so realize that my comments are about an 'older model'). I can't comment on how much it weighs but, if they use the same fabric processing (not pre-shrunk), then this gi will shrink quite a bit. The one I have is light, but not nearly as light as my Atama or Vulkan. The pants use rope which I prefer but they aren't really lightweight (maybe a 400-450g?).
Missing post moved here: http://www.bullshido.net/forums/showthread.php?t=105780