Some of the hotel bars are packed with escorts looking for clients.

was in Prague and Krakow last spring. Not sure what FKK club is but will tell you that the strip bars have private rooms where you can have some alone time with the girls. The girls working there while available in the evening seemed to be a little scandalous and pretended to not speak english when you requested certain indulgences.
The better way to go, I found is to go to a site called roska.pl (or something close to that) and have the beautiful polish girls come to you.
Most of the girls rent a apt near the city center for entertaining during the day and go home around 5-6 oclock pm just like a regular job, so it's best to plan your escapades during the day for the greatest variety.
The price was usually 200 zloty or then around $60.00 US for an hour and tipping is considered a pitious insult. Also don't expect to meet the super nasty euro sluts so common in contemporary porn, on every outing. Poland is heavily religious and the presence of the church looms everywhere.
You will meet some very sexy women if you go. I can't wait to return to Krakowthe where BBBJ is the rule rather than the exception.
It would behoove you to learn some Polish before you go.
Have fun and don't worry too much about personal safety it is so chill there, you'll see.
Drop me a line when you return and let me know how you fared, I would be especially curious to know how other cities besides Krakow were.
Cheers, fatpimento