Number 7 Guards and Knives

Hi Russel. I am by no means an expert but can tell you what works for me. I have swather guards (double guards) on my #9 and am using a knife with smooth sections. I cut around 20 acres of alfalfa (lucerne) with it this year and it worked very well for me. My three inside sections have a stub guard on them to help prevent clogging and it worked well too.
Alfalfa is easier to cut than my grass hay but still you need your knife sharp. You can cover a lot more ground with less horse sweat with a sharp knife that registers correctly.
I still think I’m going to put under serrated sections on my other mower and try it. Theoretically it cuts better than smooth sections with swather guards I’m told, but in my experience it smooth sections worked fine in a lot of different grasses and alfalfa.