price wise lots of people do 1k per level, or at least thats how it used to be!! im not sure how it is now (im in the same boat as you, i breed my own) with ratings and such, but i would say 1k per level is still fair. a W or a P on a gelding doesnt make that much of a difference because it's still a gelding and is earning you ebs regardless, some just might earn more than others.
i tend to find my SD geldings (which is most lol im a dressage breeder) do better than my AD geldings since they train up faster. ive also found dressage geldings do better than my other SD geldings, but this could be due to stronger lines since theyre all from my own breeding stock. also i havent like fully branched out and tested any of my personal theories, i just breed nice dressage boys and then geld em right away because i dont need many stallions.
i would say P+ for SD geldings are likely of the most value, and definitely focus on PPP+ for AD. i dont know of many people who keep anything SSS or lower these days, most of them get tossed out for me unless theyre too shiny for me to stand to give up.
also i'll gladly look through your stock and take a few off your hands if you'd like, i want to try to build my herd without sitting around waiting generations to breed them all!