TweetIt 4/10th's of a ml and 8/10th's of a ml, so if you go a little above the .04 then you would have a 75mg dose.
Worse case, shake, and extract with a syringe and go by the scale on it. 150mg/1ml, scale on the syringe should be in 1/10ths also, so draw to .5 ml and you have 75mg, draw to 1/3 of a cc and you have 50 mgs.
a little extra won't hurt anything.