Just as an addendum to my last, I have done a little back-of the envelope figuring with regard to recreating Cope's army.
The infantry shall consist of three, 36-figure units. I will take away three "companies" of 6 grenadiers, leaving three 30-figure and one 18-figure unit.
The dragoons shall be represented by a pair of 12-figure dragoon units each in three four-figure squadrons.
There shall be a derisory 2 guns and perhaps 3 gunners. Enough to fire them both once and one of them (perhaps) a second time.
Doing a little figuring based on a 15mm per figure frontage for the Infantry and 20mm per cavalryman, I came up with a few figures for ground scale for a Prestonpans fight.
The infantry would occupy a front of 81cm with an additional 48 cm for the cavalry and a notional 10cm for the guns. This when you throw in a few centimetres as spacers between units comes in round figures to 150cm. These are maxima which take no account of the fact that a couple of the dragoon squadrons were behind the main line of battle. Still, as they say, close enough for a game of toy soldiers.
Looking at the Battlefield Trust map of the battlefield, it becomes apparent that Cope’s line occupied a front of about 50 metres. Scaling this down to match the frontage of our wargaming units, we discover that our ground scale is in the order of 3cm to 10metres.
Musket range is therefore in the order of 15cm or 6 inches!