Hi and welcome, sadly I agree with Tiffany that the words "control" and "squirrel" don't go together. Squirrels are smart, agile and strong. They really can defeat almost any birdfeeder tricks. The scent repellent is always going to also repel the birds so that won't work, in fact the squirrrels will quickly learn it's not harmful, but the birds aren't as smart, so it could potentially scare away all the birds while the squirrels have the feeders to themselves.
I have two feeders. One is a "Squirrelbuster" like what you described, that shuts the ports if the squirrels get on the perch. Some of the young squirrels have managed to get seeds despite the clever design, but mine is tall enough that they can't hang upside down to get to the ports. I also suspend a hoop with some old window screening a couple of feet underneath the feeder so that most of the seed that the birds spread around gets caught in there. The squirrels are welcome to feed in the hoop/net and for the most part they are satisfied with that, and leave the feeder to the birds.
My second feeder station is atop a 6ft. metal pole, and I simply grease the pole with an old toothbrush and some Superlube maybe once a month or so. The squirrels can't get to it at all but it's fun to watch them try. There are actually 3 feeders suspended from that pole and none of them are accessible by the squirrels. But I do think they might try harder if they didn't have some access to the seeds from the net on the other feeder.
Squirrelbuster c/w catch net
Metal pole greased
I tried a globe cage feeder for the smaller birds, but the squirrels didn't have any trouble raiding that one: