Hi KP.
I am sure that the 50 inch would be fine, but I am glad I went with the 60 inch. It seems size appropriate for the BX. It met my expectations and I am very pleased to not be dragging around the one with the cement blocks on that you can't reach the lift for the wheels and can't back up until you do.
I wrestled with the 50 inch or 60 inch, and exchanged emails with Sawyer at CMP, and he said they both work well for a BX
Again, 50 inch would have worked fine I am sure, but the 60 inch seems more appropriate for the BX and I feel I made the right decision for me.
Let me know if you have any other questions.
Best regards,
Les.