I willl tell you what I did for more than 2 years. It was really tough. I was on the big 3 and had a wonderful doctor to help me through this. Anything I say should be checked out with your doctor/physician. First he told me to take the ethambutol with some food....eg toast before I went to bed. That way I could sleep through it. The other 2 were split up during the day. I could have dairy and other allowed foods 2 hours before or 3 hours after taking the meds. . The meds were scheduled to leave me times that I would be able to eat and observe the "rules " of timing and restrictions. I developed metal mouth and used peppermint life savers and popsicles to help kill that taste. I also wore sea bands to help if I was nauseous. It was not easy but it became a little better as I developed a schedule. At the beginning I thought it wasn't worth all this effort but over 20 years later I know it was worth it.
Anything I did to get me through this made it work. Hopefully you can access your physician and pharmacist to assist you.
Keep up the good fight.