Transmit percent

I am a newbee to WSPR. 3 hours, I think!
In WSPR 1.0 you can tell the program what the frequencies you wish to use are. In WSJT7 you can't .. are they fixed by choosing the band?
Next, in 1.0 you can give it a % to transmit. in WSJT7 you can't .. at least I havn't found it if you can. Is it fixed? Random?
Thanks in advance.