P1 countess drops multiple runes (I also believe you can have 2 or more chars in game but no more than 1 can be in tower 5), so anything over P1 drops only 1 rune in a single player assessment.
Reruns: I can only progress story on p8. After I've completed an area, I can re-run it on any player difficulty.
Shopping: I also meant to include Arrows/bolts alongside potions and scrolls, but no I do not intend to gamble at all. Shopping is strictly for supplies, I must find everything myself.
Yes, this is intended to be a very front-heavy handicapped playthrough, and less-so later on, but will still be difficult. I've completed this game many times and drew inspirated from other heavily handicapped playthroughs. Thank you for your questions and/or interest!
Countess + Multiple rune drops @ P1 is 1, if P8 it 1+ ... well that is what I used to get in full games ONLINE... SP may change things, thus I would like to see this... also, with P8 BEFORE countess in hell difficulty you have higher chances of getting High runes, I NEVER rely on Countess rune drops, I kill EVERY monster on every level of countess.
Reruns: ... You should only play P8 for drops, it is not the story line.
Shopping: ... you find more Arrows / Bolts killing and hoarding in stash with potions and TOMBS (not scrolls) ... gambling I would think you can get other items you may not have found, but hey great, keep your gold for what you shop for.
Handicapped... you are not ... to be handicapped is to play from level 1 without using Respec points and having a goal in mind for your end gear.
The above is just my interpretation, not a debate, so don't take it that way, I want to see how your run goes.
Good luck and have fun.