Whose figures are you using, as this will determine the colours of the horse furniture (eg the Perry 28mm figures have grey blankets, most others have the proper shabraques which were probably not used in the field – the 16th had light blue shabraques, broad yellow edging with a central black stripe; the 17th had a white shabraque, with white edging carrying a central black stripe).
See if you can get a copy of Mollo & McGregor’s book on the uniforms of the AWI. Both regiments wore essentially the same uniforms, with white facings and silver lace for the 17th, and dark blue facings and gold lace for the 16th – the big difference is the headgear, with the 17th wearing the “Emsdorff” helmet, and the 16th apparently adopting a new style for America, which we would now call the “Tarleton”. Horses would normally be coloured by troop – I don’t have a scheme to hand as to how they were allocated, but usually it was darkest (black) to lightest (dun) with trumpeters riding greys (white). From memory, both regiments’ officers had blue cloaks (which would be secured on top of the portmanteux just behind the rider), but of different shades with the 17th having a mazarine* blue, and royal blue for the 16th. Troopers had white and royal blue/red respectively. Trumpeters wore white coats laced red, with red waistcoats and breeches (17th), and red coats with yellow lace, and white small clothes (16th).
[*Theoretically, this is a dark blue, but on the mazarine butterfly it’s more of a greyish light blue – I’d go for the darker colour.]
Each regiment consisted of six troops, until late 1775 and early 1776 respectively, when each raised six troops of “light infantry”, each of which was added to one of the mounted troops to form a legionary corps. As fas as I can find out, the mounted and dismounted divisions of each regiment wore essentially the same uniforms, other than legwear.
Feel free to come back here if you have more questions.