Done a bit testing earlier, and it appears the numbers are about right.
Applying 6V results in 190mA flowing, so not that far of the calculate 200mA.

It also makes the motor noticeably cog when turned by hand while under power, and after connecting up the original control box, the amount of cogging feels very similar.

It does mean my plan to use some basic enclosed TB6600 drives won't work, so I'll have to go for something even smaller.