Should I rotary file the slight raised edges at the dash cracks, and perhaps fill the cracks with something prior to installing and glueing the new cover on? Anyone have good results doing this or am I going to just make a worse mess.

This possibly will be a Christmas holiday project (gift).
for my 87 300E, blue dash.

What brand is the best for fit and appearance, best adheasive?

Thanks for any advise you can give?

DanielW