the slayer is closer to Juo'nar's Grimoire than a scrappers into how price might play out. its still higher so id say around 10m. maybe more, but keep in mind most poeple who wanted close to 25sdi (and were paying for it) already have scrappers, and would probably only go for the 30s.
the high sdi one will probably average out to a bit higher than non-max old invasion spellbooks, because its significantly higher than scrappers, so maybe around 15 to 30m. old non-max that were still higher than scrapper sold well for 5ish.
in pricing these, you have to take into account what other people can use, how many of them will be available, and which ones will be collectable (only max is really a pure collectors item). For use, a couple points sdi doesnt effect cost much in my experience.