Soloing Alby Adv HM on a double EXP weekend is always fun, and if you somehow have 2x EXP potions still in reserve from when they gave them out as compensation (or just buy them individually), the mobs give an average of around 20k EXP per kill given the 4x EXP. I'm aware it's kind of an event only thing and you need to be stupidly strong to plow through it faster, but it still works. Even if MA is better with the mob exp in the later rounds, it still takes considerably more skill/damage to solo it given that you don't autopilot that. (freaking hydra rain so broken for that) I swear it makes the SM exp at the end look kind of minuscule in comparison.
If anything else is good for EXP/Gold, it may be a good thing to do Defeat Fomor Commander 2 and Battle for Taillteann 2 in a group. Stuff may be a bit tanky for some of the people here depending on difficulty, so I'm not completely sure. But it must be fairly decent if people spammed it before.
Since Final Hit became a thing, it may be a good idea to rotate through Final Hits in a party to do Conflict! an Unexpected Battle. Stuffs especially tanky, but Final Hit don't care. Not paying for repairs to get gold is also a thing with Final Hit.
It may also be a good idea for EXP to just spam the first two Cessairs that spawn before Cessair's Heart in Saga 1 EP 10. Just exit before you touch Cessair's Heart and you're good. Double EXP weekend alone made those two mobs nearly worth 50k EXP for like not even 1 minute's worth of work, although it's more of a grind having to skip through text and cut-scenes to get to it.
Conclusion, Based Double mob EXP event is acutally better than what I made it out to be before, along with the reason of having 2x combat EXP potions.
Sidenote: Only reason I mention 2x EXP is that the weekends are not stopping anytime soon.