I think 700x and red dot are a little fast for the 20.. there may be light (3/4 oz) loads for both of these, but generally the smaller gauges prefer slightly slower powders. Green Dot, Unique, PB, WSF, and the like are more towards what you are looking to use. General weight was in the 15-16 gr zone. You can check online powder manufacturer guides. Alliant and Hodgdon both offer online guidance. For the 1 oz loads, generally something like Herco, Blue Dot, and HS6 are more of what you would use.
