Ok, I'm struggling a bit to get my head around fastrack. If I have a tower router with a fairly typical setup, can I use fasttrack on certain interfaces? If so, what's the most efficient method?

Simple input filter to stop unathorise access
add action=drop chain=input src-address-list=!tik_admins

Ports 2 - 4 for wireless access points, all on one bridge - 172.16.2.0/24 - simple packet marking for queue trees and traffic measurement etc. My understanding is I can't do fastrack on these.

Port 1 for uplink & default route.

Port 5 for downlinks to two other towers. 172.16.3.0/23 etc etc
Port 6 for downlink to other towers 172.16.5.0/22 etc


As I'm not doing packet marking/queues on the downlink ports 5 & 6, could I use something like the following ?
/ip firewall filter add chain=forward out-interface=ether5 action=fasttrack-connection
/ip firewall filter add chain=forward out-interface=ether6 action=fasttrack-connection
/ip firewall filter add chain=forward in-interface=ether5 out-interface=ether1 action=fasttrack-connection
/ip firewall filter add chain=forward in-interface=ether6 out-interface=ether1 action=fasttrack-connection