hi.
The % question is a loaded question. This is because it is the absorption spectrum that is used. But if you insist in getting a single number, than I will say that for ordinary glass, 9% of spectrum is loss. For acrylic and Starphite, the percentage is about 3% or less. You can still read thru a block of acrylic 8 feet thick, but can't on a piece of glass that thick.
Assume that your glass is not tinted, anything less than 1/2 inch is not of concern.
Anything absorb energy (UV, VIS, etc) will heats up. Anything with temperature higher than the absolute zero (-273.15C) will admit radiation of some sort.
If Oceanic has something that does not loose any spectrum thru it, then they are selling you nothing (vaccuum).