The foam of a 304 wont fit in the 404 but if I change the other media to the 404 you think I'll be alright
That will be fine.
I have a 304 on my 55 gal
and always have the flow turned all the way up. If I'm ever worried about too much or not enough current I'll just turn the return nozzle toward the side of the tank and kinda bounce it off the wall.
I think a 304 is rated for up 70 gal
tanks or something. With the light load that you have it would suffice. But like somebody said earlier, you can never have enough filtration...