I only did the half dose the one time because I was worried I'd kill the Raphael catfish. This is what she does every feeding. She eats, fills up like that for a day or 2 and then goes back to normal which is why I'm thinking I need to do more frequent and smaller meals.
You don't need to worry about thet salt w/ the bottomfeeders you have, for medications, sure half-dose if you want, but even when I medicate, I do full strength and all 54 of my catfish/plecos/sharks/etc are all super-healthy and eat constantly. I actually was doing 1 TBSP per 5 gallons, and I have that in all 20 of my tanks 24/7 - 365, but I recently started doing more like 1 TBSP per 3 - 3.5 gallons, so for a 30 gallon WC, instead of adding 6 TBSP, I'm doing 8.
My fish never looked healthier and it seems they have hit quite a growth-spurt since I started increasing salt and more frequent WCs. Also, remember the warning says it MAY be sensitive to SOME scaleless fish, but it definitely doesn't say it will affect all of them