So why would a smaller (less lift) DSMB be easier to deploy at depth?
I think any DSMB would only be as buoyant as the amount of air you get in it before you release it.....so any large lift bag could be "just" 25 lbs of lift.....
That's true, but the objective is to have the SMB fully inflated when it's at the surface, so it will stand up and be fully visible to boat traffic/dive boat/buddies etc
The smaller the SMB, the less air you have to put into it at depth to have it fully inflated on the surface, the easier it is to deploy