Beekeeping in British Columbia, when we had to feed syrup, we used glass gallon-jar feeders in a box added to the top of the hive, with a telescoping cover over it.
Now I see all sorts of options. This type of feeder, sometimes called a division-board or frame feeder, seems to be popular and similar to ones included in nucs:
https://www.mannlakeltd.com/feeding-medications/bee-feeders/6-1-4-pro-feeder-3-wide-with-cap-ladder/Other feeders seem to be just plastic boxes placed on top of the hive under a telescoping lid. (Have my doubts about that one!)
https://www.mannlakeltd.com/top-feeder-inserts/Are there any guidelines for which type of syrup feeder to use when and under what circumstances? (I thought I already decided against entrance feeders, but then I ran into a post that suggested entrance feeders are a good gauge of activity in the hive without opening it. But on second thought, wouldn't mason jar feeders serve the same purpose?)
At the moment I'm particularly interested in giving new 3# packages a good start. I will get the packages late March, early April here in the Gillespie County, TX.
If the nights happen to get colder than usual, should I feed sugar instead?