Silly me,I happen to find a red dot load for 20ga
in the Lymans book.

federal paper/plastic target case w/paper basewad: 7/8oz.

rd 14.0g cci209 fed20s1 1197fps 10200lup
rd 13.0g fed209a waa20 1169 10600lup
rd 14.0g cci209 waa20 1180 9400lup
rd 14.0g cci209 rxp20 1160 9300lup

the second being most ballistically uniform,as stated in the manual.