you do not need motorcycle=yes because it is the default for all roads (and it is about access, not about oneway), nor do you need
oneway:motorcar = yes @ (08:00-20:00) because this is already in oneway=yes.
If you do it this way, it will degrade safely and be a oneway for everybody when the routing rules are very simple, but you must eventually explicitly allow more vehicle classes if they are permitted.
The other way round, you would add only one rule:
oneway:motorcar:conditional=yes@(08:00-20:00)
and no other tags, but it will create problems with routers that donāt understand conditional tagging (i.e. it would be too permissive in this case).
There are not so many of this kind of restrictions in the world, so I believe there are no best practices yet, because what is ābestā depends on tool support for the tags and how well it degrades if only simple tags are evaluated by the tool. It may also depend whether you think it is better to have occassionally a motorcar sent there during the day time (and how bad it is for them, how much detour they have to make) or have it errateously forbidding all other vehicular traffic.