Does she really need the solids right now? I wonder if you can back off and stop solids for a couple of weeks whilst you see how she settles down with this new formula - at least it would be easier to see what was causing the vomit and if different formula or meds are needed to get everything under control before introducing solids? What do you think? There is no hurry to start solids although I know for some reflux babies it is advised to begin early - it doesn't always help, depends on the LO.
In terms of routine. Tracy suggested milk feeds with the solids coming 2hrs later and top off with milk. However most routines I see are milk feeds with the solids 1hr later.
So if you are on a regular EASY then something like
milk at: 7, 11, 3, 7 (the milk feeds all stay the same as normal for some time yet, you don't want any reduction in milk intake and the idea is not to switch any of these milk feeds with solids)
solids at 8, 12, 4 (only 1 or 2 meals to begin with and you choice when it/they are. Many like to offer breakfast and/or lunch so any reactions have time to show up before BT. You don't have to offer at the same time every day as solids are just for tastes at this stage but you may find a more regular routine if you choose one meal time to focus on for solids tastes)
In the very early days my DS demanded milk immediately after a solids meal despite having had his fill of milk only an hour before, this is also what Tracy advised. After a week or two he no longer wanted the milk after solids but happily took water from a bottle and sippy cup alongside his solids meal (I initially offered water in a bottle because he could then drink to his needs, I hoped this helped to avoid constipation)
I agree with Tinkerbell about the prunes. I found carrots always made my DS more solid in his poo so I used prunes to balance him up - and equally the other way if he went a bit too soft I added carrots in the next meal.
Constipation and Laxative Foods