I used the default. Tried understanding the whole input/output thing but it doesn't really make sense to me from what I've read.
If you look on the website, it should also have an indication of fees in terms of "satoshis/byte". Since your wallet says "per KILObyte" and a kilobyte is 1000 bytes, you can multiply that "satoshis/byte" number by 1000 to get a "satoshis/kilobyte" number.
So, if it is recommending 437 satoshis/byte, you would want to tell your wallet 437000 satoshis/kilobyte. Since a satoshi is just the 8th decimal place, you can put enough zeros in front of 437000 to get 8 decimal places (0.00437000 BTC per kilobyte, or 0.00437 BTC per kilobyte).
With a 226 byte transaction that should work out to be a total of about 0.00098762 BTC in fees.
Alrighty, that part makes sense.
Thanks!