How do I assign a treatment/control according to a specific number or ratio?

Greetings,
I'm in the middle of running a survey experiment. There was a technical problem with the treatment that I only realized towards the later stages of data collection. Unfortunately, this means that the responses from those assigned to the treatment are no longer of us, and I'll thus be discarding them and resampling. My goal is to have an equal number (750) of respondents in the control and treatment conditions. I currently have 675 control respondents whose data I'll be keeping. I thus would like to configure the block randomizer so that 75 respondents are assigned to the control (so as to get to my goal of 750), and 750 are assigned to the treatment (so I'll be recruiting 825 more respondents in total). How do I do this in Qualtrics? Do I click 'edit counts' and enter 750 into the treatment field and 75 into the control field? Just want to be sure before I launch the survey again. Thanks in advance for your help.