Traben fretless4 or fretted5 for beginner??

Hiya!!

I am starting a new project where I am now learning bass guitar. I have my heart set on Traben and have been looking at a thru neck 4 string fretless as this would be perfect for the style that we are going for. However I am also looking at a fretted 5 string simply as it offers the low B string which would also be of benefit. Ultimately I will get both but which one would be best to start with???

Thanks,

Marcus