Why wouldn't you recommend the high Bb? Or conversely, why do you think that the E would be better?
Not my intention to speak for spade2you, but from my perspective I wouldn't want to be playing any bass that didn't at least incorporate the basic EADG range. Going to an A-Bb range would eliminate a critical string, for me.
OTOH, the joy of ERB's is to experiment and try new ideas, so why not give it a try?

