Have you done the glass and resin coating? Bondo is for fill and shape. I am sure you know already know that, just putting it out there. In my experience with the spray Bondo is it is easy to use, but be careful to not apply too much and loose detail. Regular Bondo seems to be a bit more tedious to apply, but easier to control the amount you apply to the detail areas. Maybe try it on a small part of the project as a test before you go and spray the whole thing and find out that it was a mistake.