Quite honestly the best advice I can give is:
1 Get a proper fitting. Really the only problem is getting your head round it, but if the wife is on board get her to come for moral support. Wherever you go I can almost guarantee that you will not be the first man they have dealt with. It may help you to phone in advance as it will reassure you that the establishment is happy to fit you and that you are expected. Bigger stores will probably suggest quiet times smaller shops (my first experience) will sometimes offer you the privacy of an appointment just before or after normal opening hours. Remember in this latter case to at least buy something, assuming you find comfort, even if it is a bit on the pricey side - it is only courteous.
2. Don't take advice from women. It is a known fact that most of them wear the wrong size themselves or dont know how to adjust them properly. There really is no need to fiddle with slipping straps nor to uncomfortable. I know the joy of taking my bra off at home, just for a change and I understand the feeling of freedom but 99%+ of days I am bra'd up from 7am to around 10pm and I know I am more comfortable with than without. In the last three years I have only spent a complete day without on a handful of occasions and usually get home and but a bra on almost immediately.
3. You could get a few bra bargains from ebay around the size you think you are and get some idea of a starting point.
4. Longline (usually has an extra wire at the side) and High apex styles are the are especially good for side boob imo
Hope this helps. Probably haven't said anything that has not already gone through your mind. Good luck
For immobilisation, stopping the jiggle and nipple comfort a properly fitted underwire with at least some padding is probably your best bet. Just be aware that it will inevitably increase your forward projection a bit. Straps that are mainly lace are cooler, but you may think that is a bridge too far
PS Option 1 really is the best with or without the wife