I only use the bleach/hardener diluted solution for a few hours and then throw it out. It really doesn't last very long in diluted form, particularly if you've used it already on some other prints the previous day. These chemicals are dirt cheap by comparison to other more normal or common chemistry. Why take a chance on the prints you took a long time to make by reusing diluted used bleach/hardener?
I see you mentioned Ilford MG IV fiber matte. That's a good paper for sure, but may I also suggest experimenting with Kentmere Fineprint VC I think it what it is. It has a pebbly finish not super smooth like the paper you're using. And it's also a bit easier to ink up and pull highlights out of. All in all I find it a very nice paper to work with for Bromoil prints. Easier to lift ink off, and correct mistakes and too heavy of inkings. It's just a nicer paper IMO, all ways around, unless you want to pile ink up altering portions of the original print. In that case the Ilford MG IV paper seems to load ink much nicer as it takes less layers to do so.