My current strategy to avoid CC fees is to use my HSBC debit card at HSBC ATMs to get my own money in the foreign currencey and pay cash for most purchases.
HSBC ATMs are in many countries but not all. In London there was no fee or percentage - in Athens there was a $1 fee regardless of amount withdrawn but no percentage.
In a recent theater week in London I withdrew cash as needed so I never had to carry too much money at one time.
I presume this would work with other banks with overseas ATMs
