I ended up replacing my crank as I drilled it on the wrong side and the motor barely moved on its own. The intense vibrations and the lack of case compression made it unridable, so I pulled the crank, threw in a spare one I have and all is good until I get some aluminum rods to fill the new holes with when I balance it properly. The more you take off though, the higher your 'sweet spot' RPM will be, some people have taken off ~33 grams from what I've read (off a 3-piece crank though), which is about 4 cubic centimeters (4ml) of material. If you remember what size hole you drilled, you can buy some aluminum rod and stick it in there (its gotta be a good fit though, not too tight though because aluminum expands at twice the size and rate as steel does, just enough that it wont want to move when the motor is still warming up), but it'll add approximately 1/3 of the weight you removed back into the crank. So if you ended up removing 33g, and replacing it with auminum, the total weight you took out would be roughly 22g, and you would retain your compression ratio.
PM me what procedure you used to balance it. I dont remember if it was you I "translated" the guides for into laymans terms. It is a long process, there's no shortcutting if you want to do it properly (very similar to extreme overclocking procedures: measure, modify, repeat. Measure is checking if the crank still rolls on its own on a level surface, modify is to remove weight from the heavy end to stop it from rolling, then check to see if it rolls again.) Being that the crank is very hard steel, its hard to do with a hand drill, a dremel could do it, I used a drill press and cutting lube.