Thanks for the cautious approach, Opo.  It's so hard to come up with a "fair price" for vintage guitars.  We all have our own approach and I do refer to the 
VG Guide as a 
guide... 
 
 
I also watch eBay prices...talk about an unreliable source of information 

 .  But eBay adds some market context.
I read guitar magazines, especially 
Vintage Guitar Magazine where I find lots of different opinions about what constitutes value.
Then there's the subjective part.  I do my homework, decide what I really want, and set my upper price limit.  My price limit may be lower than most will pay, but I take my time hunting, and always get what I want at the price I want to pay.  
I'm pretty cautious in my process, and then I do take some risks. So how do you set a value on a vintage guitar, Opo?