I thought about it, but to make the new material flush with the original surface would have meant grinding/sanding virtually all of it away, so I didn't think it made any sense. Given the rough treatment I gave it getting the hotel key cards off, I'm pretty confident that the repairs aren't going to crack off, and once they're trimmed down to final size they'll be quite small areas anyway. Fingers crossed.
My second attempt with the repair putty turned out the same as the first, despite putting double the recommended amount of catalyst in it. I'm suspicious that all the milled glass I've been putting in it is somehow impeding the cure. Whatever the cause, I've got another mess to clean up.
I think my next step is going to be a test run with just catalyzed putty with no additives, just to see if it will cure properly. If it does, I'll have a way forward with materials I have on hand, and if it doesn't, I'll be pretty sure that the putty has gone bad. I'll get that mixed up this evening and hopefully find a solid mass in the morning.
What a ridiculous waste of time...