Just fitted and seeping air all around the tyre, what's the best way to solve this?

More stans and lie them horizontally at high pressure?

Which rims?

Mavic XM819's

pump it up some more haha

you spin the wheel holding the axle ends and then do a kind of wiggle(the wheel not you.
then go ride them for a bit.

When I first fitted mine, on Rhythm rims, I noticed a bit of Stans leaking out through the tyre. Doesn't sounds as bad. Holding my wheel and swinging it around to force the sealant into all the gaps worked for me! High pressure should also do it.

Don't even need sealant with my MudX tubeless readys.

If you've got stans in there, then just give them a while (a ride will help).

What awh said ^^
Pump them up to 60psi+ and shake them and bounce the tyre on the floor. They're mega porous so don't expect them to hold pressure until after a good ride.

I had to leave mine horizontal for them to seal, but that was with cheap nasty sealant.
Stans sealed mine with a couple of shakes

Don't even need sealant with my MudX tubeless readys.

You're supposed to, and they're often reasonably porous, sounds like you got lucky.

As above, take the wheels out and give them a shake.