To clarify, in Wheeler in the Crystal Malt section, he says "The recipes usually use standard crystal malt." The color range he lists for standard crystal is 130 - 170 EBC, which translates to 50L - 60L in Lovibond. 150 EBC = 57L if you want to split the difference, thus the recommendation for 60L.
Interesting, which Wheeler book is that.
I've got
"Brew Your own real ale at home" 1993 edition
"Home brewing, the Camra guide" 1993 edition
"Brew Classic European beers at home" 1995 edition
The first two are Camra books that I purchased in the Uk, neither of which I can find any definition of which colour crystal to use beyond a general description of crystal malt (100-300EBC)
After your previous post I looked in my last book which is a US edition and I usually don't look at that much and that again doesn't have any colour descriptions in the actual recipes but does include in the general malt section a description of crystal malt that starts by saying they are 100-300EBC. However the last sentence in the crystal malt paragraph says " Crystal malt is available in a whole range of colours, but about 150EBC is the usual standard" That would be about 75L.
I wonder if the US editions of the books have a more specific definition. I seem to remember when I brewed in the UK although a very long time ago now we just bought crystal malt and I can't remember any specific colour definition. I also wonder if more recent editions have added more specific definitions, the Brew your own real ale book i have is a 1993 edition.
Not sure it really matters too much but I'd use a British crystal in the 60-75L area if you can. The British crystals I can source from my local LHBS actually give a range of values so you can only buy either 50-60L or 70-80L, I tend to go for the 70-80. Was the 60L recommendation in the Brew your own real ale at home book, I'd guess that would probably be the most available over here. Always thought it strange there was no actual definition in the actual recipes.