I will share what we do on cases such as this.
We start off by mounting 3 preoperative casts from a facebow. We make a custom incisal table that we will use once the case is prepared. We do a diagnostic wax up to check movements/esthetic's. We take the second preop and prep the cast and make reduction matrix's and shell temps. We check all movements again trying not to alter guidance with the temps. If we are adding significant length its often hard to impossible not to. At this point we present our concerns to the client who has a consultation with the patient to educate them on our findings. This is all done before a hand piece has ever been picked up. The costs associated with this makes all but the most serious clients shutter but all it takes is one big case to fail and they will see the benefit.
This is how we proceed with many of my clients.
We start off with a full mouth exam, charting, and radiographs of the patients existing condition. Patient's desires are taken into account. Impressions and facebow
taken for study models. Consultaion with clinician(s) about the challenges of the case. Full diagnostic wax up with notes pertaining to difficulties achieving patient's
desires. Another consultaion with patient explaining all treatment options from full mouth to leaving them in current situation or getting a second opinion.
If patient agrees to treatment, preperation matrix and temporaries made in office from diagnostic wax up. Guidance double checked and shape of temps worked out in patient's mouth.
Patient gets to 'test drive' temps to see how well they tolerate any changes to verticle, guidance, etc. Upon patient approval, impressions are taken of temps and
we proceed with finished prosthetic. Starting with the end in mind certainly gets you there with a lot less headaches.