>for spring built-up can you just feed sugar water, or do you have to feed pollen patties also?
They won't build up in the spring unless they have adequate stores of honey and adequate amounts of pollen. If there is a lot of pollen in the hive, it may not make much difference if you feed pollen. If there is not it will make a lot of difference. The same with stores. If they are at all light in stores they will hesitate to start raising a lot of brood. If they have syrup then they get the impression that there is a source of nectar coming in and they are more willing to raise brood.
To distill that down, it makes a lot of difference if they don't have it.
Once there is a source of fresh pollen they tend to ignore the pollen patties.