Recently i found a new online bitcoin roulette which accepted bitcoin, so i decided to give it a try. i registered and deposited some amount {the nice part was that i got 50% bonus on that}. after some nice playing i made 15x my initial deposit, however after 24 hours playing i decided to put the whole amount on BLACK. And as you can imagine this bet made my day black too. i lost everything.

After couple days i went there again and made a bigger deposit, luckily i won a lot of times and made some big money. this time i did not bet on black and withdraw the money immediately.

Thanks to that winning streak, now i have some decent amount of bitcoins in my wallet. I plan to go back to the roulette and try to win some more, so the questions is if i win some bigger amount {lets say over 100 bitcoins} where should i withdraw and safe-keep them? coinbase? circle?
if i keep them in some of these and if i decide to exchange them to cash, how long it will take for that?

I also contacted Bitcoin Beveren and asked if it is possible to send me the funds in fiat. The answer was positive but they said there will be a fee of at least 3%.

So what is the best option here?