I was going to get some of these guys' brethren, the 'Widowmakers', for VSF Russians. The Widowmakers are snipers that arguably look even more Vostroyan; but I didn't know about these guys with the rifles, thought the Winter Guard only came with axes and hand cannons.
The size issue could well be a problem for VSF, it's a good point. I think these guys would probably tower a long way over my Ironclad British line infantry.