In a couple weeks we’ll release light cavalry for Tercio, the 30YW range. Both mounted harquebusiers (both command and troopers) and the croats, eastern european light cavalry (both command and troopers).
Those lights will be mounted on smaller horses, more suitable for their battle role than the warhorses of the heavier armoured companies.
As you can see those are a not just a “downscaled” version of the heavies but realistic smaller breeds. Below you have pictures of the miniatures fully sculpted and with heavy riders for reference.
Of course you would like to use those little horses to represent badly mounted heavy troopers.