Is it OK to use the word 了 on 很 + adjective phrase, to emphasize?
很...了 is not that common. When you say 俄罗斯女人很漂亮了, it could mean either 俄罗斯女人确实很漂亮(truly beautiful) or 俄罗斯女人已经很漂亮了(beautiful enough already). 

But if you add 已经， it will be natural. 俄罗斯女人已经很漂亮了，which implies 俄罗斯女人 is beautiful enough already, (and you might not have to look for other women.)

Maybe, you could take 已经很...了 as a structure, meaning it's already ... enough. For example, 已经很好了(it's already good enough)，已经很强了(It's already strong enough)，已经很喜欢了('I' already liked it enough)，....