I haven't used the 3m product, but use similar sprays.
You can apply directly to the mould and the fabric will stick fine. Due to your release agent, it will not stick when you come to de mould
As for the residue, the aerofix stuff I use does leave a bit of a pattern if used too heavily, but it your not using a gel coat, it polishes right off. Would have thought it would be the same as the 3m stuff