I'm going to feed the tiny swarm I picked up yesterday with a jelly jar over a hole in the inner cover directly over the cluster. I don't want any other bees getting to it, so no HBH or vinegar. I'm pretty sure they will take right to it.
For a weak hive, you want to feed a continuous but fairly small supply of 1:1 syrup and protein, since I'm sure what you really want is a stronger hive. Once you have decent bee numbers, you can then feed up to winter weight if you need to in the fall. This time of year they will store excess, so you need to stimulate them to make bees instead. They will make comb to do so.
I'm feeding my spring package about a quart a day of syrup, but can't always get out there every day with it, but last time I looked they had drawn the second medium I put on about half way to depth and were storing some honey. I want them to draw that out completely and fill it with nectar/syrup honey by fall, but if we get soybean nectar I don't want it full of syrup right now.
I don't think you will ever get bees to draw empty comb and put nothing in it -- they draw to use, and if they have no need for brood due to lack of resources, and no nectar to store, won't take syrup and won't draw anything. Over feed and they make "syrup honey", which is fine but not if you are trying to get real honey.
Feeders should always be completely inside the hive and sealed off from outside bees, as otherwise you will set of a robbing frenzy once the spring flow is over. No attractants or feeding "stimulants" either, the scent will draw foreign bees and again set off a robbing frenzy. Bad news, that -- lost a hive last year to robbers.