Yes, you very well *might* pop the bulb. Just let them rest for a while. I think I've seen Silverfox recommend a half an hour. I've always let them rest for a couple of hours, but then, I've never really been in a hurry either.
Not too long ago I instaflashed a WA1185 with Duracell 2650's rested for a 30 mins. This was AFTER using Progold on all the contacts including the batteries as well as doing the tail spring fix. Before the Progold and tail-spring fix 30mins off the charger would not instaflash the bulb. Now I let them rest for about 90mins. and haven't had any problems.