You shouldn't experience crashes at all.
Just open the item_kinds1 with notebook. Search for arrows, or bolts. Find the part "blabla_arrows_flying" or "blabla_bolts_flying". Replace those parts with "flying_missile". Do it for every type of item (tatar arrows, bodkin arrows, etc.) There should be 6 per each item you see on the website, for different loomed versions. That's all. Just save them and start playing.
If you mess it up, you can repair the files from crpg launcher.
It sounds a bit complicated when I tell it like this, but it really isn't.