I have had great results with 18 gr of Promo with the combo you have. Oddly enough, I only use Fed 209A (until supplies are gone), and Rios. 19.5 gr is a little faster and may make you more confident on caps.
I use ~16+ of Promo with that combo. Pressures are so low I don't worry too much about lot-to-lot density differences with that Promo load. Current jug is throwing ~16.5 grains. Last lot threw ~16.0. I couldn't tell any difference.
I have no problem with that load at skeet, nor for the small amount of Sporting and 16 yard trap I shoot. Dunno about handicap trap. Your mileage may vary.