Well if you can, use Reload after every wash para laging slick ung surface.
I've heard some negatives regarding Gliss. May hazing on some users.
Best is if you can purchase Carpro EliXir (new product for 2019). And use that after every wash.
Ako naman I use P&S Bead Maker after every wash. Its a polymer spray sealant. Super slick and hydrophobic ung surface after applying and curing. Paint is also very glossy after.