Unit speed musings

[FM WarB]

There is a difference between short term battlefield speed and long term day long march speed.
10 inf and 14 cav speeds are about right for battlefield speed. Inf sometimes quick time or doubletime marches or changes formation on the battlefield. 10 Mps give inf a realistic movement factor on the battlefield. Same with cav who are sometimes cantering or charging (but unfortunately don't have to change into line to charge).
10 inf and 14 cav are too fast for days' long strategic march speed. Even with no night movement, that gives inf the ability potentially to make a preposterous 72 km march in an 18 hour day. Cav could move a horse killing 100+ km in an 18 hour day. No stopping for rest and food, saddle off horse's back and fodder. Not even Stonewall Jackson's boys or the Zulus move that fast.
For scenario design purposes, this means give units historical entry times with long marches and they will reach their destinations faster than historically. Designing the oob with cav squadrons, gun sections and large inf bns spilt up lengthens the march columns but only partially alleviates the problem. In a multi day battle, entry times can be made later so units arrive at first night destinations at historical times. But which wargamer is going to wait two or three hours on the morning of day two to let the stragglers catch up?
As is, which should be used, battlefield or strategic march speeds? Is there a compromise speed that doesn't screw up both? I am not asking these questions without a proposed solution. (Here I go again.) Lets have a march fatigue/march straggling optional rule along the lines of Panzer Campaigns.