Can you just go to the interface and turn off the 2.4 signal?
I personally do not like Helix, at least on the specs side of things. reading the offering on videotron sites the max you can get connected to it are 12, in my house with the array of devices we have this is not enough (3 phones, 2 tvs,1 chromecast, 2 DVDs, 1 printer, 2 laptos, 3 tablets). So anyone visiting my house will not be able to use the wifi either.