Wellcome jjmouris!
Just did a test to make sure, 405 nm light from our laser shines thru water very well, just as i thought there is no noticeable drop in cure rate going thru 2 cm of water.
I think water carry's Blue light very well, and lots of deep sea creatures emit blue light, taking advantage of this.... googling.....
looks like we(405nm) just snuck in !
http://library.thinkquest.org/26153/...ages/elec1.jpg
Looking forward to testing this idea out. There is a liquid that would help by being above the resin I think it would do so with its adhesion properties not its mass which.
In fact i think the mass of the water on top the resin would make things worse not better, as there will be less pressure difference in a void filled by water than a void filed by air.
As for the pro we have high hopes of accomplishing everything you mention, but are still in the early stages of R and D.