Making a buck is probably the 'proper' way to do it plus it means you have the source to make further panels should you be unfortunate enough to damage the one on the car (whilst the wife borrows the car of course
)
Kitcarman could probably point you in the right direction about making the mold and creating the panels but it just sounds like either not enough release agent was applied or not applied correctly if the panel stuck in the mold.
But I think any of your methods will be ok.
Cheers, John
Madabout-kitcars.com