It would be nice to be able to set a single parcel weight limit on each courier service and have this used to calculate parcel quantities on an order where the courier service is used. An offshore option may also help where the limits are different.
The only way to change the parcel quantity at the moment is "Units Per Parcel" and "Additional parcels required when despatching" on products but this doesn't work when you have different product on an order that might fit in one package and be within the weight limit.
Setting this idea to Already exists, with the above comment as the solution.
You can set parcel qty rules based on weight here https://om.mintsoft.co.uk/Shipping/CourierParcelQuantities