Smiths Falls guy here, just messaged you as well.
Between a friend and myself we have 4 new hives this season, my two are doing well and his two are somewhat behind. I've been reading alot and asking alot of questions as well and will be attending the Lanark Beekeepers annual summer meeting on Sunday with a list of questions to ask experienced beekeepers. I am also wondering about fall feeding, when that should start ... I do know you should be feeding with a 2:1 sugar syrup. You should be checking for mites as well, but if your hives are new they would have been treated beforehand. I am using green drone frames as part of my IPM, we recently removed 4 and found no mites in the cells ... which is great.
Regarding your weaker hive, I would reverse the brood chambers immediately ... the bees always move upwards. The empty bottom deep, should be placed over the full top deep now ... thats something you normally would do in the spring because the cluster will move upward during the winter.
I have also read to start feeding earlier than later, but I also want to ask to some other beekeepers.
I was planning to feed starting mid September, temperature has alot to do with how active the bees will be.