Civilian flying is prohibited during flight school in the Army (along with scuba, skydiving, and all sorts of random activities). That is waiverable on a case by case basis, like if you need to stay current or get checked out. That said, there are a lot of people who do it anyway. The CFIs in the area for FW also teach at Fort Rucker and if they wanted to boot you they technically could. I haven't known anyone who got booted for violating the list of prohibited activities, but that's that. Do what your career can handle. In WOCS you'll have no time for flying. Right after WOCS while you are waiting to start flight school (4-5 months these days) you will be doing a whole lot of nothing. You could fly in the evenings then. Weekends are usually free, but from what I hear once flight school got real backed up they started flying on Saturdays as well.

Out in the real Army, the WOs usually go home by 3 or 4, RLOs stay till 7 or so. I have not had time to go do my civilian FW stuff in my spare time but am getting to a point now where I can free up some time to do so. Out here there is a lot of stuff to do and paying $150/hour to fly when I get paid to fly anyway hasn't been a priority. Infantry dudes have time to fly if they want, but I don't know too many who do, or who want to pay that much money to do it.