Motorways and the ol' Plungy are not for me. Learnt my lesson twice. Major Engine failure on the MI at Newport Pagnell featured in my introductory post. Then when back on the road, riding up the M5 from Barnt Green to West Bromwich, at night, in the rain, no leg shields, like being in a washing machine and getting splashed by the trucks.
The motor kept going, but as I approached Junction 1 to come off, realised water had got into the throttle cable and the throttle was jammed. Managed to use the cut out on the handlebars to make erratic and scary progress to a place of safety.
If you choose to regularly use the motorway, a 20 tooth gearbox sprocket would be a good choice for a more relaxed, less frantic cruise speed.
As for cruising at maximum revs, I suppose it will be fine until something major drops off or it goes BANG in a big way. I value my wedding tackle and don't fancy a 60 year old alloy rod making a guest appearance, so it's a light throttle and mechanical sympathy from me.
Swarfy.