i think the timing is perfect, i play on max difficulty and when they arrive (around 250ish) i'm just about ready to join them (army size of around 160, lvl 30character) they get hit fairly hard if u don't help them, most of the time they get wiped out within 50 days, so you have to be in your late.

also u can do all the quests before hand

I have 300 something cuz i just grinded recruiting unsullied, dothraki and hedge knights. but the timing is kind of wack tho tbh but everything else is good.