I like VF-11 better than regular fertilizers, so yes, I would recommend it. As for your kerrii, it's hard to say what the problem is. If it's budding up, that doesn't necessarily mean it's ok as it's not uncommon for a failing plant to flower in kind of a last ditch effort to seed and live on that way. If it's drooping, I'd say it's not taking up water, so I would repot it. Kerrii has a pretty hefty root system, so if it's in a tiny pot, it may just need more room.

Denise in Omaha

VF-11 is one of the best made plant products on the market today!
Heck yes try it and you will see for yourself. It is especially good for shocked or stressed plants when you trade or buy cuttings. I water with it on newly purchased potted plants too for any stress they might of incurred or have.
Fact being I water with it most every watering on the stable plants too! haha.
Take the plunge!,,,Debbie

I don't have any experience with VF-11, but in my knowledge it is not recommended/allowed to fertilize a stressed plant or cutting that don't have any roots.
Usually I don't fertilize any of my hoya's they satisfied with less then many other plants.