It could work just fine, good idea!
I tried to use 40 mm face mill, but part starts to vibrate/ flutter like there's no
tomorrow. It's only 1.3 mm thick at the center, so I was expecting that but I had to try. Finish cut is made with regular 10mm, 4flute HSS end mill.
use so small amount of tools as possible and avoid manual tool changes. I try
to find multiple tasks for each tool if it's possible.