Ok--so here are my thoughts. Again, my thoughts and not intended to offend or hurt feelings.
First, I don't have the boat anymore I sold it in 2007. Consequently, I cannot provide you the dimensions. However, I am pretty sure when I called Johnson to have the top made they had the specs on my boat.
Second, you get what you pay for. When I first got the boat I got a bimini from Overtons that looks very similar to what Harold has on his boat. After a few years of use I found it not very durable and it got dirty very easily on trips back and forth down the highway. Frankly, it started to look cheap. As a result I decided to upgrade to the Johnson. I want to say I paid 500-600$ for the Johnson versus 250-350$ for the Overtons. But, you get a custom color along with stainless vs aluminum and plastic.
Next, how do you want to mount it? At the time, I was doing a lot of trailering which required me to put the bimini up and down a lot. Additionally, since we were 60 mph plus on the trailer I either had to tie the bimini down to prevent it from blowing up in the air, or remove it and lay it in the boat. I quickly tired of this chore and when I bought the Johnson went with the stanchions in the rear. This was a decision I never regretted.
Last, if you think you will ever consider adding a "Fly High" pole you might want to inquire about having heavy duty zippers sewn in.
I loved the Johnson and thought it was worth the money. I got a ton of comments on it and it complimented the boat well.