Question about FVRCP vaccine

I have 3 adult cats who I'm vaccinating for FVRCP, but I am slightly confused as to the vaccine schedule. I had read initially that for them I would need to vaccinate, and then booster 4 weeks later, then again in a year, and then every 3 years, which I was all set to do. But then I read that if I am using a MLV (I am) I should only do one initial vaccine, then booster in a year and then every 3 years. So I wouldn't booster 4 weeks after the initial shot. 

Does anyone have any advice? It would be greatly appreciated! 

If you're giving MLV vaccines to adults, then yes, you only need to do one shot initially. Killed vaccines need two within a few weeks of each other to produce immunity, MLV only need one.

Whether they ever need any boosters is debatable, but if you do give them you can wait a year or more for the first one.