I'm shooting a lot of Multigrade IV RC Deluxe - I rate it at ISO4 and it's doing ok. As someone else mentioned, paper is good for low contrast scenes - 3 or 3 1/2 stops the way I shoot it.

I'm preflashing by laying the paper on the floor, holding a keychain LED flashlight against the ceiling and lighting it for a sec. If I immediately developed the paper at that point, it'd look white. If I flashlight it for 2 seconds, it starts developing as super light grey - that's how I know 1 second is enough (learned through trials on small sheets of paper and developing).

I tray develop in the evenings in my bathroom with a headlamp that has red LEDs. About 40-100 seconds in Ilford Paper Developer does the trick for me. I dilute at 1+12.