I expect you'll outnumber us, though perhaps not by much. Bear in mind TCU is a small school, with an undergraduate enrollment of around 10K. We've got something like 70K-80K living alumni worldwide. This is why we roll our eyes at people who mock us for a stadium seating 45,000 - if it's full of students and alumni, it's a significant portion of all the people on the planet with a direct connection to the university.
We also (if I'm to be completely honest) spent most of the second half of the 20th century sucking at football, so a lot of folks graduated without absorbing that school spirit aspect of ardently supporting the team. Some of us ('92 graduate myself) are exceptions to that. Obviously, 20 years of success has created a lot more devotion from the Fort Worth community than there was when I was in school, but I don't know how many fans we have that never attended the school. Certainly nothing like the legions traditionally successful big state schools can muster.
Then there's the fact this game was supposed to be at Amon Carter and part of our season ticket package, but has now been moved 20 miles away and we're being asked to shell out more money to attend. This has been discussed ad nauseum around here, and I'm not passing judgment either way, just saying it may be a factor in some people not coming.
That's a lot of talking to come around to me thinking you'll probably enjoy a 60/40 crowd advantage.