I don't know how I came across it, but Thomson's Rule for First-Time Telescope Makers seems relevant here: : "It is faster to make a four-inch mirror then a si

I don't know how I came across it, but Thomson's Rule for First-Time Telescope Makers seems relevant here: : "It is faster to make a four-inch mirror then a six-inch mirror than to make a six-inch mirror." http://wiki.c2.com/?TelescopeRule http://wiki.c2.com/?TelescopeRule