That is, I just write in Russian text in the comments for each boot screen, and you paste it?I don't have Russian translations for the texts on the loading screens. That's your job! But if you provide the translations, in proper Cyrillic letters, I can copy them onto the screens as I did for that "Start New Game" screen.
The font used for English and Spanish is Dolphin Bold. It does not include Cyrillic characters, so it can not be used for Russian. That is why I used a different font for the Russian "Start New Game" screen.
Translated file RESOURCE\INI\TEXTS\RUSSIAN\Storyline\storyline_strings.txt, thanks @EugeneFox , I've tweaked it a bit and now it's ready...