any opinions on the pros and cons of 47mm vs 58mm tubes?
My thoughts were; 58mm is heavier and more expensive but collects ~27% more per tube 47mm is lighter and cheaper per tube. At low solar angles it may be slightly more efficient and depending on your asthetic sense, they look better Looking at current prices from one Irish supplier (and using the rated output they provide), 47mm works out cheaper per kW eg a 20 tube panel would be E389 vs E417 per kW
58mm tubes are 1.8m long whereas 47mm are 1.5m long. most cars can transport a 1.5m tube but not a 1.8m tube. shorter tubes are also easier to fit on a tighter spot on a roof, such as a small garage or shed roof, the 'corner' of a hip roof, etc.
58mm tubes are often quoted as 50% greater output than a 47mm tube, which (from memory) is exactly the increase afforded by the bigger aperture of the inner tube plus the longer length. despite this, i've heard several knowledgable persons commenting that the actual output increase is less than 50% more than that of a 47mm tube, so what you are saying sounds reasonable.
how many tubes are in your EURquote for the 58mm tubed panel?