For silhouette sanctioning, just call the NRA and follow the options to the silhouette section of the competition division. Ask for Greg Conner. He'll send you what you need in order to apply.
If you want an example of a club program -- which you'll need to submit along with your application -- advise me here and I'll post one that we use. (All the silhouette programs we use are similar, all we do is change the descriptive wording from highpower to smallbore to airgun, etc.)
It will be interesting to see how you progress.
In my experience, what you're proposing is like trying to mix oil and water.
Aside from the fact that sanctioned SB silhouette is a demanding game --which limits the participation and automatically makes you a minority voice in any club decisions (AKIHMSA's 'big targets, cheap guns, easy scores, heavy attendance' program doesn't have national standing yet!) -- you're trying to bring very widely divergent personalities together.
Shotgun competitors are often 'social shooters'. Around here, every club that we see with a shotgun facility soon winds up diverting most of the funds to the trap/skeet programs. (Shotgun tends to attract the 'country-club' shooting set and they always seem to usurp the political side of club operations very quickly. Once that occurs, watch what happens to the 'balanced spending' of the club treasury...)
And benchrest is a 'buy-the-match' game -- BIG time. (If you complain about trying to fund an 'equipment race' in silhouette rifles, try competing against stool-shooters who figure that buying a dozen match-grade barrels a year is just one of the MANY ancillary costs of playing.)
While this may be the 'future of shooting' in your area (I assume that you don't mean that you control the future of shooting nationwide), I'll be interested in seeing how well it works. And even more interested in seeing if it's still working a year or two from now.
I do wish you luck -- I hope that anyone promoting shooting participation succeeds -- but it's hard to paddle upstream...and I think you're putting your canoe into the wrong end of the quick-water!
Before you start labelling this as 'defeatist', think about these points:
I've been a club board member and a club officer.
I am a match director.
I do promote shooting and youth involvement at every opportunity.
But I'm also a realist.
IOW, 'Been there, done that, got the T-shirt!' ;-)
Keep us informed. You might figure out something that all the rest of us have missed!