traylee: Isn't it frustrating when you can't work out what one you need...they used to make little cans of formula, but they stopped making them, which is annoying when you are trying to find the right one!
You can get s26 and karicare in an AR formulation, they contain a thickener which helps the formula thicken in the stomach....its designed for reflux babies, and the thickening helps prevent it from coming back up.
In general formulas are all the same consistency (well, thats been my experience), but the AR (Anti-Reflux) ones get thicker as they cool down.

Is it possible that Eli has a lactose sensitivity. I think there is at least one formula thats available from the supermarket that seems to help with this...and theres one (which used to be chemist only, but may now be available in the supermarket) called Lactogen...I used to look after a little girl who chucked alot on formula, but when she went onto the lactogen it all settled down.
She wasn't lactose intolerant as such, and went on to cows milk at 12 months etc, and could eat cheese and yoghurt etc once solids were introduced...
It is a common thing...perhaps thats worth a shot?

The only drawback is, I know that there are no sample sachets available for lactogen....