Addendum to prior article, October 2009:

The wood bow came in three styles: All 1500 type, thin-flat, no center latch. - AFH1746 Early 1600 type, thicker-beveled, a bit of overhang at top rear to hold the center latch. - AFH6671 Late 1600 and 1600-MK-II, longer at the ends. - AFH6846 - This holds the slightly wider rag top with overhanging flanges above the side curtains, and was introduced along with the change of articulation of the top frame at Car No. 78249.

The early 1600 type bow can be used on the 1500 if you want to install the center latch (or when the early part is no longer available). The late 1600 type bow can be used for earlier (narrower) rag tops if you shorten (cut down) the ends of the wood bow to meet earlier dimensions (about 3/4-inch on each end). Using the longer late 1600 type bow with earlier (narrow) rag tops results in the downward hanging side flaps being a little too high at front and too far out, holding the side curtains away from the windscreen posts. If you run into this situation after the top is installed, you have to burst some stitches near the front to let the hanging flap move inboard.

Addendum November 2010
Photo below left shows the side flap curving upward at the front. This results from using the longer wood bow (MK-II style) with the earlier narrower 1500 or 1600 type canopy. Note also that some stitches have been burst to allow the hanging flap to move inward to be flush to the windscreen side post, and that results in the flap hanging down near the front. Photo below right shows the wider MK-II style canopy installed with the correct longer wood bow. Here the side flap lies straight as intended. (Click for larger pictures).

For the problem shown at left, aside from tearing it all apart to shorten the wood bow and re-do the installation, a more immediate fix is to burst some stitching to separate the side flap to allow it to move inward so the side curtains will mate to the windscreen frame. The resulting loose fabric flap is irritating, but not so bad as wind and rain blowing around the side of the windscreen into the cockpit.

When the later MK-II style wider wood bow and canopy were introduced (at Car No. 78249), the Service Parts List states that the earlier parts are no longer available later parts should be used. This implies that the later parts were intended to supersede the earlier parts, so replacement parts for early 1600 should be changed to the later top style. Most concours enthusiasts do not agree with this, and indeed the earlier 1600 type canopies are widely available today (but beg for the shorter wood bow or cut down the longer one).

Addendum, December 2011:
Here are two more pictures showing the results of using the longer later style wood bow with the earlier and narrower canopy. Big mistake in both cases.

Pictures below show the fix for this problem. Trim the third type long wood bow back about 3/4-inch on each end. Squae it off some, and do not run into the bushing tab slot, as it still needs to hold tacks or staples.

Above, wood bow before and after trimming.
Below, new 1500 or early 1600 top with correct fit.

The last five photos provided by Jeff Rodrigues in Houston, Texas.