What client are you using? For basic inbox/outbox setup, 4 is plenty. Some clients, like #Amethyst, have far more robust relay settings for a lot more control over which relays are used for what purpose.
Discussion
#gossip is more powerful and implements inbox/outbox better as I can see
I used to use gossip, but i need speed for web and mobile
I switch between at least 4 different clients and i think it might mess them up. Nostrudel satellite primal , my own client and any others that come up like snort or jumble, etc
It shouldn't other than Primal. Never change your relays in Primal. They will ALL be listed as both inbox and outbox relays if you do.
The other clients you mentioned all seem to respect which relays you have set for inbox and which for outbox, though I admittedly haven't checked to see how HiveTalk handles relay settings. 😉
Some clients, like Nostrudel and Jumble have relay lists that are only used within that application. Changing those should not affect your relay settings anywhere else.