Welcome to the moving Caravan @Reinhardt !
Interesting to see someone else playing 1.09 classic! I’ve been playing this exact mode a lot recently (\"a lot\" is a bit of an exaggeration right now, lots of other priorities in my life for the time being haha).
IMO, the Paladin and Necromancer are the weakest classes in 1.09 Classic. If you find a classic Paladin build that can handle Hell CS on Players 8 easily, please let me know! My Paladin is stuck in his 60s, and given how weak he is, even with really good gear, I have to level in NM on P8, because Hell is still a bit too slow to be worth it
As for leveling in 1.09 Classic, generally speaking, Cow level is best until level 87-88, depending on the class. At this point the levels are slower than going to 99 in LoD lol. Then CS all the way, and Urdars on RoF are good for a while, too.
But for melee characters, so only Pal and Barb, Cow level in Classic is unviable, so you’re better off running River of Flame, you actually get more XP per hour there than in Chaos Sanctuary based on my experience (as long as you save and exit when you get Blood Maggots, because they slow doen runs way too much).
By level 86, CS is about the same rate as River of Flame, but Doom Knights in CS give a pitiful 600~ XP, on players 8, so you’re better off skipping them when you can. So what I do is use the WP from City of the Damned, run River of Flame. If I see blood maggots, I go back to town and use RoF WP and run straight to CS. If I see an XP shrine during the run, I activate it just before dealing the killing blow on Diablo.
I believe this method is best until level 91, at which point it is better to just kill uniques and champs, seals + Diablo and skip everything else.
Then when you get super high level, switch to Players 1, find an XP shrine, pop seals, kill the seal bosses, switch to PLayers 8, spawn Diablo, get the shrine, and kill Diablo with the shrine active. I tested a bit with Hero Editor on a level 98 I created. On players 8, Unique and Champion monsters only give ~3k xp, all white mobs in RoF and CS give 400-600 XP, and Diablo gives 88k (131k with XP shrine). I doubt anyone will ever get there haha.
IMO, only Barb and Amazon can reliably and quickly run RoF and CS on Players 8. Necro is out of the question. Sorc might be possible with super high level static and good FCR, but other spells are either too slow or too low damage, runs would take a while, unless killing only Diablo on players 8?
Necro is AMAZING in the cow level, so he can realistically reach level 91, with a lot of grinding. At level 98 though, Cow level gives only ~20k XP total on Players 8 lol, which means more than 14500 cow runs.