Actually, it's all about the finish more than the gain.
WA-DW is a non-permeable material whose surface just bounces back light. There is no absorption whatsoever.
I disagree about the 3010 needing a .8 gain surface. Certainly it can handle one....no doubts there, but dulling out an image intentionally is a exercise in waste.
Then there is the lessening of light output while in 3D mode. Once you've gone with a sub-1.0 gain surface, there is no restoring the reflectivity back. Dull 3D is not good 3D
entakesflight, seems obvious that someone referred you to the DIY Forum about WA-DW, and "all that praise" about it was all that you read about. Well I'm betting that you did not read about many...if any 3010 owners, or anyone else for that matter, who had PJs over 1600 lumens and opted to go with WA-DW. That was an application well suited for 1200 lumen and under PJs as being a great "Hang-n-Shoot" no paint option.
It still is. under those circumstances.
You have only two viable choices.
1. Get a Neutral Density Filter to stop down the light output of the 3010. That's a well know and simple fix that might be just the ticket to ride on.
2. Paint over that most excellent Substrate with a 1.2-1.4 gain Gray. This is the BEST solution, as the 3010 still falls short as far as having exceptional Contrast (...It's brightness is a contributing factor in that...) and a reflective Gray (Flat sheen'ed) will boost the perception of having much better Contrast.
That is the primary reasoning behind Kirnak's suggestion...and it's entirely valid. Where we differ is that I see no sense in correcting a problem by robbing Peter to pay Paul. The ND Filter can be had in several values, so your not restricted to just accepting a gross reduction in brightness like a ,8 gain surface would offer.
I'm truly sorry you did not read more thoroughly about all the other alternatives we offer here on DIY Screens before jumping onto the WA-DW train. I will leave you with this however. If you determine you want maximum performance and image quality, we do have some very viable solutions waiting that can coat that WA-DW surface and get you to exactly where you want to be.