What is your electricity rate in your country?
If your rate(Electricity cost) is above 0.1/Kwh it won't make any profit instead you will get a negative profit only if the dragonmit you talking about is the T1 unit?
Dragonmint t1 power consumption is around 1480W with 16th/s so if your electricity cost is 0.12 USD you won't make any profit.
About payout, I think they don't have options to manually withdraw your mined BTC from slushpool they have a paypout threshold minimum of 0.001.
Anyway, I just login to my old account you can find the threshold payouts under profile you can find it top right corner.
It looks like this
Then looks like this
If how much BTC you have in your wallet sample the threshold limit is 0.1 and you didn't reach that amount and you only have around 0.003 you can set the threshold limit to 0.001(As their minimum). So that the 0.003 BTC you have will send/withdraw automatically to your external wallet.