Well, there goes another beautiful theory slayed by an ugly fact!
The excellent: The syringe worked perfectly for filling the holes with urethane. I used the type you can get in the pharmacy for giving infants/children medicine. It has a short, blunt plastic snout. Good for sucking urethane out of the can and positioning and putting in a precise amount in the hole.
The good: The painter's tape was about 90-95% efficient at keeping urethane in the holes. I was able to fill the holes no problem but I got a bit of seepage.
The bad: The syringe was inefficient at removing urethane because it had a short snout and couldn't reach the bottom of the holes.
The good: After switching to a rubber infant's nasal aspirator bulb with a longer snout, I was able to get about 60-75%% of the urethane out of the holes.
The bad: The nasal aspirator couldn't be used to put the recycled urethane back in the next set of holes because it tended to "burp" air and make a complete mess.
Summation: In the end, the urethane didn't get recycled from one set of holes to the next and I still made a bit of a mess when the tape was pulled, but the syringe and tape ultimately got the job done!
Thanks, everyone, for your suggestions.
Al