Digital BW, The Print

I like to mount my prints directly on 1 in. thick black gatorboard with 
no frame or glass.  I've found a local Shop that does a great job at a 
reasonable price.  It works well for high contrast B&W images IMO.  
Adding 3/4 in. spacers also floats the print off the wall. Also, in 
Photoshop I add a 1 in. black border to the print edge.  I'll usually 
use Harman fb gloss paper or Epson VFA or other matte papers on my 3800 
using ABW. I top it off with with 3 med. coats of Printshield spray.  
After 2 years I see no issues what so ever.  It presents in my opinion 
a clean contemporary look that I use only at my home.  An advantage is 
you can put large prints in small wall space areas like condos because 
of no matte or frame.  

However, I know this method is not archival if I wish to sell these 
prints mounted this way.  I know there is info out there but its 
somewhat confusing as to what actually works...?  I'm also looking for 
a method thats relatively low hassle to apply because of limited time 
and space.  Perhaps a heavy coat varnish type sealer that provides 
suitable protection against dust & UV but does not affect the 
appearance of the print in a major way. The method could be rolled on,  
maybe even a spray can, or a low cost sprayer.  And if a sprayer, any 
equipment recommendations?  
Thanks!
SteveB