I know what she's going to suggest, you know what she's going to suggest - you need to tell her fuck straight off with that one and tell her what you had to put yourself through and that you would not accept a single drop of it ever again as if you thought It was an effective drug for taper purposes you would have used it in such a way last time instead of putting yourself through hell in order to just be free of the shit once and for all.
I don't know the equipotency of the fent doses you have been on in relation to the OM you have been given, but it might be worth just bigging it up as much as you can to convince her that she doesn't have to 'think about what to do next', as you feel that you have been given the best medicine now to control your pain and also for use as a taper substitute as it doesn't have the latency when it comes to the final, hopefully minor, w/d symptoms when you jump off at the end. You just need to steer her towards the right prep now, for starters you need to remind her about extensive history of opiate / opioid bsed pain management and how much and how little you found the various drugs and preparations effective due to the treatment rotation.
You appreciate that she is responsible for and has to account for her prescribing, and that your not there to tell her how to do her job, but another polite reminder wouldn't go amiss, such as the fact that your an experienced health care professional who has to often make independent decisions yourself about treating people with narcotics, on many occasions when you do not have the luxury of time to 'think about what to do next' 'and that with regards to your own health you have been through the mill from every direction and ultimately you know better than anyone what treatments you have found effective AND relatively comfortable to stop at the earliest opportunity. Perhaps suspensions, tinctures, liquid medicines, whatever you call them, might not be as good on your tummy as a tablets would be as as liquids just hit your guts instantly and are imbibed to quickly (physeptone makes me want to chuck buckets for the first 10 mins after I take it).
So after pointing all that back to her, if she is comfortable prescribing Orabul, then why not just change the preparation, 'would I be able have the equivalent dose via MSTs for a week or so and if I get on with them ok, we can continue using them for both the pain management and for discontinuation of the treatment once appropriate'.
Just so she has a stick for the carrots, emphasise the short term 'trial' of the tablets (MS tabs were your preferred analgesic and you first choice for taper purposes were they not, or did I make that up?) and that you will see her regularly if agrees to carry on prescribing them, so she can 'monitor' things as they go on and that by seeing her regularly you can begin the taper as soon as your comfortable enough to as you don't want to take one more single pill than is absolutely necessary (that one always works a treat) the general idea being that she will be able to retain overall control of the treatment regime, but without limiting your patient choice, something that she should feel ethically compelled to honour due to your high level of knowledge in medical manners such as this and your own personal experience due to the long periods of serious illness you have had to endure and the difficulties you have had in discontinuing long acting narcotic type medicines.
If you can sell the whole process to her as a 'team effort' involving a highly intelligent patient who has vast experience in the use of gold standard opiates / oids both from a patient and a prescribers perspective (as regardless of any standard protocols you use when out in the van - if your colleagues and you are personally making decisions regarding the administration of the sort of things we discussed in OD the other day then you are a prescriber as far as I'm concerned) it might mitigate this horseshit comment on 'thinking what to do' as you should be able to provide the environment for her to confidently treat you with the medicines that you know will suit you best. Sandwich your assertion between the professional empathy - some doctors are just brick walls and there's not a lot you can in those situations, but anyone who has to 'sleep' over a treatment plan like this should be well open to some basic Derren Brown hedfuckery so you can get what you need to get better and get opiate free again as soon as is feasible.