So....I cut about 1/4" of the pen spring off and tried it. It worked ok but not great. I removed it and cut off one more coil and it seems to be just enough to function properly in single and double action......so far. Edit to add...just for clarification, this was an "unloaded" function test. I still need to get to a range for a live fire test.
How long it will last however is another story that will only reveal itself over time.
I am planning on taking pics of the quick fix and posting them as soon as I can. In the mean time in between time, if anyone has a source for the proper spring, please let me know.