My one problem with forge..

Okay so ive started forging properly… and i mean actually making a map, so far i seem to be getting to grips fine after fiddling for about an hour and a half getting used to controls and its coming to me fairly fluently now… little bit slow still but thats to be expected, the problem im having though is i cant seem to get anything straight… theyve done it so the position its currently in if you flip it on 45 degrees, itll do 45 degrees of its current position and not 45 degrees to level almost like previous halos, i may have missed something but i cant seem to get anything level… something always seems to be slightly out which throws loads more out… and yes, im a perfectionist when it comes to forge xD
Has anyone found a good way or THE way to make thing perfectly level and straight? because i cant find it… woulda been much easier if they had done it like previous halos and if you flipped it to 90 degrees itll go 90 degrees to a certain level built into the map…