I would recommend for him to read the numerous articles in the excellent Smoothbore Ordonnance Journal, in case - the gunners of the Kavalleriegeschütz - name already explains that it has something to do with horses or cavalry - rode on the carriage trail of the gun and not compared to the French artillery á cheval - on horses (with the exception at the beginning where out of 9 artillerie légčre batteries - 6 of them the gunners mounted on the so called Wurst) - and no the faulty Toussard is wrong that the Austrians rode on the ammuniton carriage, they rode on the trail of the gun carriage as already described and the construction of the gun tube was even different to take this into account.
The equestion would be how mobile was the French horse artillery compared to the Austrian? Not much - in case even slower there the poor French gunners had to rely on a very cumbersome 4 wheeler ammunition waggon, whereas the Austrians used pack horses.
One has to see the complete picture and not just horses.
The British, Prussian and Russian system was maybe the fastest, using two wheeled limbers which included ammunition supply.
Maybe the Russians due to having excellent tack and horses had the most mobile horse artillery.