GAI grades versus PSA/SGC

[Brianruns10]

Hey All,

Normally I buy PSA, and to a lesser extent SGC (which I eventually cross). However, I'm considering my first GAI buy, as there is an auction now for a very nice, well centered Duke Snider card, for my 52 topps set. Having never bought GAI though, I'm unsure how well those cards cross over to PSA. I'd expect they tend to grade higher, so I should expect a loss when it goes to PSA. What I'm trying to figure out is how much of a loss should I expect so as to not overpay? The card is graded 8 by GAI, and it would definitely get at least 6.5 to 7 by my eye.

What has your experience been? And is GAI pretty reliable when it comes to spotting altered cards? I'd hate to buy one only to get an Altered qualifier from PSA!