Help - what to feed a cat that has urinary cystitis AND vomits if fed too much at once?

Our female cat Fern is almost 10 years old now.  She has always had a problem with eating too much and then throwing up.  More recently, she got to a point where she could self-regulate her consumption of dry food well enough to not throw up too terribly often.  However, in the last year or so she has developed urinary tract idiopathic cystitis (no bacterial or crystals/stone detected), and more often than not her urine has blood in it. 

I'm aware of the recommendations for idiopathic cystitis, including the suggestion not to feed the cat any dry food.  This has been impractical for us, however, because if Fern is given a sizable serving of wet food she will eat it immediately and then throw up.  We give her 3 or 4 smaller wet food servings per day, but this isn't enough food for her overall, so she still ends up eating a fair bit of kibble.  We can't do much better on giving her more wet food feedings because we're not home for the entire day. 

Is there any dry food that could actually help a cat with idiopathic cystitis?  I know there are urinary tract foods out there, but they mainly seem intended to prevent stones, which is probably not an issue here.  Or is there anything else you'd suggest feeding?

Thanks so much for any suggestions.  - Fern's Humans

Have you tried placing a billiard ball in her dish? This slows down the eating process.

Hmm, since most adult indoor cats only need one 5.5-oz can a day (depending on the calorie count of that brand/flavor and the cat's size/activity level), if you can feed her 4 times a day that's only 1.375 oz at a time. . .is she able to keep that much down? If not, how much do you think she can keep down at one time? The main thing for cystitis is that she gets enough water, and dry food just isn't helpful for that, even if it's "formulated for urinary health".

If you think she's throwing up because of eating too fast, putting something large in the bowl or using one of the slow-eating bowls they sell at pet stores might help. If you think she's throwing up because her tummy just can't hold much at once, that's a little harder :/.

Absolutely NO DRY KIBBLE! Even if vet prescribes dry urinary tract health ei science diet, Hills royal . Some vets, and I just don't understand why, still recommend dry high carb and grain food. Well, I actually I do understand why. Cause there is money to be made for them by supporting greedy big pet food companies. Not seeing that vet any more. Get Wellness grain free chicken, turkey, beef,. Try to avoid fish About $2 for 5.5 oz in Honolulu. 12 oz can is more economical. Better yet , you can eventually make your own raw food but you must follow a good recipe to make sure it is balanced. But for right now and from here on, wet food only. I am adamant because of my own tragically expensive ($7,000 vet bill last year due to chronic crystals).
If vomiting is frequent, kitty is getting dehydrated. Not good. The wet food has lots of moisture which they need but if throwing it up guess it doesn't matter. Lots of info on line.
Wishing your kitty good health.

Thanks a lot for the suggestions.  Maybe her eating issue is more about stomach capacity instead of eating rate, because she'll often wait ~15 minutes after eating and then throw up.  Happens with dry and wet food, unfortunately.  I think Fern can only eat about half an ounce of wet food at a time.

I just ordered an automatic feeder that can keep wet food cool (catmate c50).  Using that to feed her while we're at work, we should be able to greatly increase the proportion of wet food in Fern's diet.  Will also experiment with spiked water (adding bonito flakes or tuna juice) to encourage more drinking.