Hacking An (un)important question about DSiWare downgrading

[Justin14p]

So, I have got:
-A hacked 2DS (A9LH + Luma3DS) [with my brother's account],
-An unhacked New 3DS (11.0.0-33E, browserhax+menuhax) [with my account],
-Freakyforms Deluxe (cartridge version, duh)
-And I'll buy Fieldrunners

And I want to do a DSiWare downgrade on my New 3DS, but what's better:
Doing this right now (and my brother's account will stuck on New 3DS) or just wait untill 3ds dsiwarehax installer will be released and do this using only New 3DS (my account will stay on New 3DS)?