TR2/3/3A Top web and fitting question

This is my first TR3 top install. Looking at it I would think I set the front bar first measuring from the rear snap on the car to the front seam. Then set the rest of the seams to the bars. Is this correct? How would you do this project? Thanks , Bob I will post a pic soon. There really is a TR in my MG garage!

After some research I found a site that says 15 3/4 up from the rear deck, 8" to the next bar and the front bar sits 4" above a horizontal line from the top of the windshield. Now that I have that done and the rear lift the dot snaps in at the back(not the sides yet) The top appears to be a big stretch to the windshield. Do I mark center and lower the frame and start installing the front snaps? Then hope it will stretch enough to go up and not crack the windshield? I am working with a Robbins canvas top. Bob

Set the rear bar first, then measure and set the middle bar, then the front bar. The top frame relies entirely on the tape for positioning of the bars vis a vis each other and the tonneau saddle. Measurements need to be with the top snapped on and the bars positioned against the top, one at a time, for tightness. The seams don't tell the story.
Bob

PS The top is a big stretch every time you put it on. Make sure it is warm when you lay it out the first time and install the tape. When you put the top on in daily use, the frame is erected under the snapped on top by pulling on the tabs at the base of the rear bar.
Bob

Thanks Bob,'
I guess I will go out and lower the frame so I can install the front snaps. I did try to stretch the webbing since the top would be pulling on it when installed so the lengths would match what I found on line. Wish me luck I'm goin' in. Bob

Rather than fit my new top to an old Amco measurement (which I have a print of), I set my frame to the seams in the top. The Amco measurements didn't work for my frame and top.

So in this regard, I would suggest measuring what you've got and making your own diagram. I used a fabric marker/pencil and many tape bits with marks to check and to keep it in alignment as I progressed. You want the frame bows to end up under the seams. I used clamps to pinch the webbing to the bows for adjustment and marked around the edges of the webbing plates with a fabric pencil.
When I finally thought I had it all fine and re-measured a couple of times, I started in the centerline of the car back to front and worked my way from this centerline to each side.

I took my time over a couple of days on and off to get it perfect. It's been staying tight in any weather.

You are correct to set the three bars to the three seams or pleats in the top. Just beware of doing this in a cold area where the top will be shrunken and then stretch out when it gets warm in the sun.
Charley

At the shop we cheat a little and put an electric heater in the car to warm up
the top while it is fitted up(sitting on a fire blanket of course). We also use seat
belt material for the webbing. Make sure that you have a good quality top
before you start,there are some awfull ones out there that can cause you to say
bad things......
MD(mad dog)