Please keep us posted.
I'm thinking about trying RL19, N160 (which isn't even listed, oddly enough) or H4831 when I can get around to buying some 200 .20x.
For what it worth here's Nosler's data for comparison sake, I know it's a different bullet but it might be a good cross reference for starting loads maybe.
A 200gr bullet at 2900fps out of a WSM in a 26" barrel seems a bit l slow to me, considering I could hit 2900-2950fps with the 195gr Berger and a 23" barrel with my 7mm SS.
I wonder if that Tejas round from across Canyon Arms could find any extra horsepower with their improvements to hit 3000+ fps...