Japanese and Allied Cavalry in BoB

[Boggler]

I'm thinking of getting a handful of mongol irregular cavalry for my Japanese army but I'm not sure whether to get the Copplestone Chahars or the standard mongol cavalry packs. I would prefer the Chahars but would they be appropriate for a Japanese irregular cavalry unit?

From my limited googling it appears that the Chahar region was occupied by Japan in the late 30's so i'm guessing I could use the Chahars in the Back of Beyond at an earlier date?

[Ignatieff]

Mixture of both might be appropriate.  The Chahar figures are regulars, and therefore are uniform in appearance.  The Mongols are true irregulars, so if you only went for one type, it would have to be them

[Boggler]

Thanks