I've been playing an upright for 10 years, mainly classical music with arco and some pizz at church. The music director at church would like me to play bass guitar on some contemporary pieces. So, I need to get an ax and learn how to play it. I'm wondering if I should start off with a 4 or 5 string? (I did a search and couldn't find any previous postings on the subject). Thanks for your help on this.