[OldSchool]

MrE,  To answer your queries, I went with the double pane windows (I believe they were called "model 1800".  They cost a bit more, but provide better sound and heat/cold insulation factors.  I bought them some time ago, so I don't remember the price exactly, but I seem to recall about $5000 for all 10 windows.  They arrived in a very nifty deep coffin-looking box.  They were beautifully packaged in foam slots with tons of foam.  Not a scratch or crack anywhere on them.  Of note, I changed the design of the windows to exactly what I wanted.  In the four corners, I specified low T-bar style.  This ensures I always have a shady window from whence to draw cooler air, via the roof-centred fantastic fan.  The low T-bars also provide un-fettered viewing from the pilot and co-pilot seats.  I believe the small openings also provide more security (too small for a man to crawl thru, even when open).  I purposely went with "boring" unencumbered glass for all the other windows.  My sight-lines within the salon and dining areas are now absolutely excellent (I dislike looking around seams/handles).  It was a very big job and making that first cut was nerve-wracking, but I don't regret any aspect of the job.  If curious, I cut out all 10 windows (perfect rectangles), measured 3 times, and then placed my order.  I was able to easily repurpose the (longer) vertical aluminium framing into the (shorter) new vertical spaces (as shown in the pictures).  Overall, a great upgrade for our Classics.