What does Number of script verification threads do in DigiByte-qt and what should I set them to, right now there set to 0.

What does Size of database cache do and what should I set them to, right now there set to 100 MB, will this make me a faster node.

Am I a node? I got 29 in and 29 out, but I don't see very much activity in Network Traffic. 31 MB in and 87 MB out. in the last 4 days. other qt use about 275 MB out a day.