Where you are building up a colony (so no crop supers on), the only downside to feeding (apart from the slight cost of some sugar) is making sure that you don't let them store so much that HMQ runs out of space to lay.
The less drawn comb you have, the narrower the tightrope you must walk!
If you REALLY don't know how things are going (maybe you aren't used to hefting a new hive), opening up to see is probably less risky than heading for either starvation or swarming. Scylla or Charybdis?
If you are checking for laying space and stores, don't waste lid-off time on a cool day checking that the queen is there let alone trying to spot her.
If your worry is about whether laying space or stores running out, then get the lid back on absolutely as soon as that question is settled.
One solid frame of stores should keep a nuc going for a couple of weeks, especially since they will try and pop out during any brief gap in the weather. If you can grab the opportunity as well, you can maybe save yourself some worry.
