IMO, Dyne is okay in certain situations, but it's not a cure all and it's very high in sugar. The reason I said I would not give it undiluted is because some people get it in their heads that "if a little is good.........." Next thing you know, it's an entire syringe three times a day. I just think it's safer to mix it into something.
I have mixed it into critical care and I have used it in the water bottle (in addition to a regular water bottle). I personally wouldn't give it straight from the bottle. I would rather use Life line and Critical Care than Dyne if I was trying to gain weight back on a chin. Slow and steady, not quick fix. A cheerio with Dyne on it is "junk food" for a chin. I'd rather see the weight go back on in a healthy manner.
When I have a chin I need to gain weight I use Life Line, Critical Care, and canned pumpkin (straight pumpkin, not pie mix) as a blend and give it however many times a day I think it's necessary. Right now I have a girl whose top two teeth broke off for absolutely no reason, and she's getting 120 mL of this mix a day, broken up into 3 feedings.