Just a follow-up. My son-in-law works for a Honda dealer and managed to borrow their Duramix gun and a dual tube of the filler. The gun requires a new nozzle each time you use it because the stuff sets up in just over a minute. Good news is that nozzles are about a buck a piece at the autobody supply store. Other good news is that while fiddling around, I was able to squeeze enough of the two materials out of the tubes by hand, mix them and get the holes filled with no problem, so it is very possible to use Duramix (for the two 1/4" holes I had to fill) without the $50 gun. Pretty neat stuff, available in different flavors for different types of bumper plastic. Car is now all black and cleared, waiting for wet sanding to begin. Whoops, the hood is still waiting to be painted, as I have filled the window washer nozzle holes and am fabricating an "under the cowl" system for the squirters. We're havin' fun now!