i would use a sealer but i would be careful about putting it on to heavy ppg has a urethane sealer. i would not use epoxy.i have not used 2035 clear as far as 2042 goes i have painted many completes with it i'm from minnesota and 2042 works well for completes except in summer.dbu is and old basecoat it has a enamel base so it dries slower. dbc dries faster thats why i recomend it over dbu and like someone else said it does not cover as well. what i do on cars i want to look nice is put on a couple coats of color let it dry over night wetsand with 600 or 8oo grit that lets paint dry good and knocks out the dust nubs giving you a nice smooth base for the rest of the job. you have to scuff all the base before recoating it.