Stacking square bales with grapple

I was wondering how many bales high y'all usually stack small squares 14x18x36 bales with or without a grappler. I was wondering how many bales high I could go before it became unsafe or started squishing and damaging the bottom bales. I have been going 6 bales high but was wondering how far I could go and what works out good for everybody.

Stacking square bales with grapple