I was going to order an acme tow dolly, but on a whim I called my RV Dealer and asked if they had any used tow dollies for sale. They had a bunch to my surprise. I picked up a Kar Kaddy SS for less than I was going to pay for the Acme Dolly.
I know that didn't answer your question, but thought it was worth putting out there.
As far as the supplemental brakes...I would recommend them...under normal conditions you might not need them, but if you ever have to "hard Brake" you will be glad you have them, they will allow the MH to brake its weight while the dolly will brake the weight of the tow vehicle....resulting in a reduced distance to stop.
2014 Georgetown XL 352QS
2013 Days Camped-10 (in a rental)
2014 Days Camped-52
2015 Days Camped-53
2016 Days Camped-32