I've biked over 2500 hours or 30,000 miles in the last five years and have used lots of hydration products. The first thing I'd say is practice using the product on workout days and NOT for the first time during an event. Same goes for food or fuel like gels and bars. It takes time to train your body or intestinal system to process this stuff especially when you're trying to go fast. A friend of mine name Neil Shirley used to be the editor of Road Bike Action magazine and his research said you can only really take in about 500 calories an hour and that liquid calories is the best form if at very high pace. That takes time to get used to. If you drink a lot of sugar and eat a lot of sugar you can very easily get what I call sugar rot. It's that sick feeling in your stomach from consuming so much sugar. It doesn't usually come on for me until I've had about 5 bottles of Gatorade, 3 or 4 gels and other food bars. Once you get sugar rot you won't want to drink anything other than water and if so your performance will suffer. Taking tablets like Nuun are good for slower paced rides on ones where you don't need as much sugar for faster efforts or you are getting your sugar from things like gels. I've never tried salt tablets but when i do long rides indoors I take the odd pinch of salt and pop it into my mouth. I've used the Scratch stuff in a similar way to the Nuun tablets and it works the same way except there's no carbonation that upsets my stomach.
The idea of using a gel capsule and bypassing your mouth and stomach is interesting. One concern is that the mind and body responds to the taste of sugar in your mouth and there's a strong correlation between the taste of sugar and effort levels. I forget why that is.