Hello,
I changed the design of faucet and amount for withdrawal is calculated automatically now.
Amount is calculated in range (min - max) and with probability:

0.25 - 0.5 BTC   => 88.889%
0.5 - 1 BTC   => 10%
1 - 2 BTC      => 1%
1.5 - 3 BTC   => 0.1%
2 - 4 BTC      => 0.01%
2.5 - 5 BTC   => 0.001%

Best regards