KirkD - The +10 SubSee is 200g in water and the +5 SubSee is 140g in water. On land, they are 345g and 240g, respectively.
The new SubSee adapters do not use a set screw design like in the past (or like the Aquatica mounts). Instead, we use a circumferential o-ring clamp system, which applies an even pressure around the entire port, holding it in place much tighter than ever before.
In the worst case, when using a dual-hinge adapter with both the +5 and +10 lenses installed, it will add approximately 0.75lb to the rig. I don't often hear people complain about this, but you could certainly add a float belt around the port to compensate.
Keri Wilk | ReefNet Inc. | www.reefnet.ca | 888-819-REEF or 905-608-9373
If it would not be to kuch trouble, could you post a picture of this new mount. The picture on the website shows 3 screws. Thanks