Ive been following the frame squaring guide but things have been getting worse the more i follow it. I havent touched the motor mount sides, only addressing A and B. The rear seems really badly out of square and im tempted just to completely rebuild. Although i did build with a DIN875 the first time and im not sure how i could get the frame any squarer. Corner to corner was within 0.5 of a mm. Should i check for bent extrusions?