Wow, what a tough one. When I used to homecook I used a multi-vitamin powder from Only Natural Pet. For calcium, I used eggshells (pretty much tasteless). Have you tried powders or are you crushing up vitamins bc crushed vitamins usually have a stronger smell?
For me,
one of the reasons I moved to raw was bc of the balancing of supplementation - even with all of my research and everything I thought I knew, it still made me feel insecure. With raw, you don't need to supplement. And, raw just made more sense to me as being more species appropriate. My guys are healthier than ever.
That said, I think dogs can be healthy on premium dog food, homecooked, or raw (the latter being the best, imho) - you just have to find what feels best for you and your dog - and go from there.