Digi's are the easiest things in the world to use, and trust me you won't look back. I used to think i was good at judging the weights by eye, but i realised how inaccurate i was once i purchased a set of digi's. With regards to your short bag, id call him back tell him your short and ask what he's gonna do about it! If he tells u to play on the motorway or whatever, cut your losses and find another dealer. It aint worth gettin into hot water over a few grams!

Peace

Buddy