It seems to me, that broadcasting to more relays shouldn't decrease your performance too much.

I'm seeing this note of yours on 6 of my relays in Nostros, meaning that we have quite a few of overlapping relays. It's taken a little while to see them all though (screenshot included).

Amethyst has the ability to turn off up or down feeds from specific relays. I think I'm going to play with that some more.