Don’t use magic at the Fourth Harrowing, have the Helots form a trial, don’t plunder the town in any way. Your choice of rations in the first week is pretty important, but I would generally recommend full rations for anyone who is sick, and either subsistence rations for all healthy people or subsistence rations for the children and 3/4rds rations for the healthy adults. You will want to adjust this to subsistence rations to all healthy adults and full rations to the rest as soon as you can, so preferably on week 2 or 3.
First week your main priority will be to just get food to survive and to get mules so that you can survive the coming weeks. Sell a mule, buy as much food as you can without getting complaints (27, I think?). Scout for mules, steal mules from merchants/yeomen, ask Helots for food and send away as many children as you can. Send the remaining bandits out to hunt rabbits or anything you fancy.
Sabotaging the Harrowers is actually a good way of getting some cred among the Helots and if you sift sands instead of burning them it is also a way to increase the size of your band for a small amount of anarchy, if you let Breden explain things to the Helots. So I generally do that. You should also want to send out some scouts to look for nearby temples to fund your food purchases. As soon as your scouts find mules to steal, send out another scouting party to find even more.
Asking sympathetic Helots for food and money, and to care for your children, is a pretty standard action every week. Buy food often, do not be afraid to sell a mule to get more food. If you want to fight the army in the final chapter, setting up a couple of traps might not be the worst idea. Or you can try to teach people how to read. Raiding a Tithe barn is a great way of getting a lot of food, but you might get Theurge’d when you have no mules ready.
Stay away from raiding anything dangerous unless it is likely to give you something valuable. The tax collector’s convoy is pretty dangerous and gives you a bit of anarchy, but you can probably take it out if you want to. The money is really useful. I didn’t actually do that in my test playthrough though, mostly because I forgot.
I had 11 anarchy by the end of Winter, and you need 20 or 21 for Simon/Suzanne to not show up, so there was room for more shenanigans.
To deal with Hector… Well, if you are a noble I would suggest talking to Hector’s sister, although that requires being in love with Hector. I don’t think trying to attack Hector is a great idea, so probably best to hit back at their wealth and use Theurgy discreetly to help you out.
For the final battle, you should not be known as a Theurge so you should be able to wipe out all the Theurges on your own. That should help you out a lot, no matter which plan you go with.
Hope this helped.