PLS need to know wich is best way to do the following

i have router od with 3 interfaces
ether1 is uplink on ip 212.98.x.x
eher2 is satellite downlink ip 82.198.x.x
ether 3 is giving internet to my customers

first i enable1 nat on the ether 1 to all connected to ether 3 ,and defaut route is added to the default gateway of the uplink cz i want to keep allports going thru uplink cz it is fiber and i run all the mikrotik all fully working , and the downlink is working also i can ping the ip from the internet
i just want to forward all http traffic to the downlink ip , is it better to put the downlink ip in the src address of the squid or to make prefered source on the default route as the downlink ip ?
thanks in advance