I have not come across any standard practice for mapping cycle routes except the wikis below. If you thnk the current wikis are wrong you could put a proposal in.  https://wiki.openstreetmap.org/wiki/Cycle_routes#Tagging_cycle_route_networks
and
https://wiki.openstreetmap.org/wiki/Tag:network=lcn?uselang=en-GB

I can't make the normal routing apps see the lcn relations so I doubt they look beyond the highway tags and ignore relations when route planning.