Given that you have another dump already I would say option A. If you will be keeping the other dump then why do you need two? If you ever regret the decision you can always add one back on later. You can probably sell the box and hoist together for more than just the box separately. There really aren't all that many things that I would put on a flatbed that I would need(or want to) dump off.

You mentioned the extra height, which will make loading a little harder, but you didn't mention the extra weight. Why pull all that extra weight around with you all the time if you aren't going to have a use for it. Also If insurance is a lot higher that is a factor as well. I would not play games with them by not telling them it is a dump truck, because you won't like how they play....by denying that you are covered. That's not something to find out after an accident.

Tad

1946 Chevy OS 1.5ton, 1955 GMC 3100, along with other various IH,Ford,Nash,MGB,.....