Lucky just got diagnosed with a grade 2. I have been giving him CoQ10 and just ordered some Taurine to supplement. People also say Vitamin E. I am adding one supplement at a time since Lucky has tummy issues.
I'm also changing Lucky to a fish based food so hopefully he can get a lot of his Omega 3's from the food - he has not done great in the past when I have tried to supplement fish oil (diarrhea). I posted when Lucky was diagnosed last month and got some great tips. I also posted on MonicaSegal.com's Facebook page and she gave some suggestions.
Good luck. Glad it is slight. My normal vet missed Lucky's murmur too - I'm also in NJ. Lucky got diagnosed at the show in October. There is a heart clinic in Clinton NJ in January. YOu might want to take him there to have the cardiologist listen again. You could also have a heart echo done there for a discounted price so you have a baseline and can monitor progression. The cardiologist at Lucky's clinic also recommended baseline blood pressure & bloodwork.
(a.k.a. Lucky's & Sparky's mom!)