set unitspermint=2 so forging 2elems need 1 nxt coin . if set unitspermint=100 forging 100 elems only need 1 nxtcoin ?
yup. Just depends on variance, cpu and how lucky you are. The higher you set your unitsperMint the higher the difficulty to mint a block becomes for you. The higher it becomes the more likely it takes longer for you to get anything.
It could be instant with unitsPerMint=100 or it could be days if not weeks if you are unlucky.
Just a helpful hint - I have an 8 core CPU and am minting 100 ELEMS for 1 NXT tx. It takes me about 1 day to get the 100. In the long run - if server disconnects or you lose internet connection, you start over at 0.