Advantaliate is definitely the nuclear option when it comes to Record Keeper. It does leave you really light defensively, assuming you don't have a natural wall relic (Tyro's Sentinel's Grimoire and Y'shtola's Thyrus staff).

Got through all of the bonus battles today. My biggest problem was making Sap hit Seymour. Changed from Shadowsteel to Venom Buster which hit first time and I beat him first time from there.