Most brown cafes are not cool with dope. Coffee shops (where you buy the weed) are. There are also a couple of places whre there are bars and cs's next to each other, so you can buy a smoke and enjoy it with a beer (eg ricks and susie's saloon if memory serves). I wouldn't smoke in your hotel unless you know it's ok - you are just creating potential stress. You can always ask, this is amsterdam, they will have been asked before and are unlikely to be offended even if they say no.
Good coffee shops can advise on strains of weed - tell them what you want. I have had nice mellow weed from Green Place before. Places on my hitlist for the next trip are Katsu and Voyagers
http://www.coffeeshop.freeuk.com/index.htm is a good resource, loads of people ask similar questions to yours.
Enjoy!