Re: feeding pollen
I like pollen and sub but I'm not a fan of just buying it, tossing it on and waiting for the best to happen. Feeding should be well thought out; given at a time when the bees can both get to it and use it appropriately; and then not stopping until there's plenty of real food that the bees can haul in and use. If done correctly, your bees stand a good chance of building up soon and doing well. If you mess up, you may have a brood bump that mother nature cannot sustain and, if you miss continued feeding, you'll have a major drop in populations.
Up here in New England I've had times when the hive came into early spring bursting at the seams and I stopped feeding, only to witness cold snaps that dried up the food supply forcing me to get back in and supplement. If I hadn't thought it out, I'd have seen some starvation (and I have in the past).
When I fed, I preferred real pollen to subs although quality subs work better than none at all.
Finally, don't ignore the space as you build your colonies up. For me, "dandelion time" is swarm season. On a built up colony, it could happen sooner and you may be caught off guard. How many of us have inspected a colony one weekend and found it satisfyingly healthy only to watch it swarm a week or so later. Feeding sub should make you adjust your late winter / early spring management plans to earlier dates......much the same way you've moved the natural buildup timing of your colonies.
"My wife always wanted girls. Just not thousands and thousands of them......"