12 lead EKG

i have another question on EKGs...so that is what i mainly do in my cardiology office...but recently ive been questioning how i do them...you see a lot of people are overweight or woman with "a chest" which makes it more difficult to find their ribs(intercostal spaces )....hopefully you get what im trying to say ...its ending up that im guessing where im putting them...and where it may still read correctly...i just want to know what other people do when they cannot physcially feel the intercostal spaces....??? any advice...i didn two patients who i did today...trying to get to where they should go...v4 is one of the hardest placements for me so if i cannot find the 5th intercostal space ...i resort to just putting it under the left breast...just looking out for my patients!!!!.........thanks so much ....

A friend told me to check out taking a 12 lead EKG course....know of any in Orange County NY??? thanks!!

Christy~