Firstly, haven't dealt with 'founder' in my own horses, but have dealt with 'low grade laminitis' & IR in a couple of mine, and have dealt with many & varied degrees of laminitis/founder in client's horses. And 'typical outcome' is 'it depends'. Depends how chronic the problems & distortions in the hooves are as to whether/how long it takes to get them completely over it. Depends on the causes & whether this can be completely 'corrected' - Eg. I have one friend I had to just quit trimming for, because she WILL NOT SEE that her horses are obese & do not need the barrels of feed she throws at them, despite the fact that they both become laminitic EVERY YEAR and she spends a fortune on the vets, who also tell her her horses are obese...
But then, there are owners that diligently do everything within their power & the horse still has probs, due to hind gut damage, disease(PPID for eg) or some such. And then there are the horses who are rescued or otherwise simply 'too far gone' by the time the problems are addressed, and many of these will only make it back to 'paddock sound' without boots. A few I've come across are too far gone for even that, and unfortunately I've had a couple of clients who ended up putting their horse down because it was constantly suffering with little chance of getting substantially better. But these days, with the knowledge we have, it's actually a rare case that horses can't at least be brought back to paddock soundness, and very many get back to true soundness & being able to work comfortably.
after two rounds of drugs and x-rays, she is still quite lame with a mild coffin bone rotation in both front hooves. Now on hay in a dry lot 24/7.
Drugs, as in bute may well be a 'necessary evil' but as it is known to cause gut damage & that damage can *cause* laminitis, so perpetuate or worsen the problem! So I'd suggest that the horse is on bute or such for as little time as absolutely necessary. Ensure that she has yielding footing &/or padded feet(highly recommend Easycare Cloud boots if you're in the market but not bought any yet) and that she is in an environment she can walk if she likes, but doesn't feel compelled. Ensure she has a place she is comfortable lying down, to get off her feet completely when needed. Then you should be able to eliminate the drugs. I'd also be giving her gut support/repair supps, to try to counter any damage.
People(including vets not well versed in nutrition) often say get the horse off grass and onto grass hay. This is not necessarily bad advice in the least, but as a 'blanket statement' without consideration for all factors, it is not necessarily helpful. That's because grass does not lose sugar content after it's cut & dried - that means that if your hay came from a 'rich' field, it may well be just as sugary, even more so, than the paddock you're keeping your horse off! Depends on type of grass, maturity of grass, how it's grown, even weather & time of day it's cut, as it gains sugars with photosynthesis. But with hay, at least if it is rich, you can soak & drain it before feeding, to leach out some of the sugars.
And nutritional balance is very important for health, esp regarding 'founder'. Particularly look into supping extra magnesium & chromium, especially if you think IR or rich feed could have been behind it. And ensure iron & potassium levels are kept relatively low. You may have discovered these, but there are a couple of great websites, particularly helpful for understanding how diet & nutrition impacts. They are safergrass.org and ecirhorse.com
She has had a new ferrier out to cut her heels down and her toes back to reduce the laminar wedge
Yes, vital that mechanics are corrected, and if heels are high, being the cause of 'rotation', they do need to come down, but should be done gradually. Stretched toes however, can be brought back/relieved to the 'ideal' amount immediately & for the sake of the horse's comfort, as well as how quickly healing can happen, it should be done ASAP. ELPO guidelines are sound principles, to learn how to 'map' the feet & work out precise a/p(front to back) balance. The only 'condition' to following those guidelines is if your horse has a very pronounced 'ski tip' due to the founder being very chronic & severe, in which case you may need to leave the toe a little longer. You said you have xrays though, so you/the farrier should know precisely how much toe can go.
You're welcome to (first see the link in my signature for what's needed) pist hoof photos & the rads, if you'd like any specific opinions/feedback.