Thanks so much, everyone! I did go ahead and order the SKS chainboard. It's a risk of my $25, I know, because it may or may not work with my particular combination of frame and derailleur. I'm up for the risk, though! If it doesn't work I'll probably try the hebie or OGK. Once I have a working chainguard I'll post pictures.

I just bought a second bike which came fully chain-guarded, and to me it's a huge difference. I immediately resolved to get a chainguard for my first bike. I know there are those out there who consider them unnecessary and detrimental to the bike, but it just comes down to individual needs. I ride in San Francisco up some impressive hills, and need a full gear range for my commuter bike. I also often jump off my bike and into meetings with funders and executives. I also like to wear skirts and wide-leg trousers, and I find changing at work impractical. The combination of all that spells, to me: A front derailleur and a chainguard if possible.