35mm internal rims are pretty wide for the road. I'd suggest getting a second set at about 25mm or narrower for faster tires. The hubs just need to be disc ready to accommodate rotors. Just make sure the spacing matches what you currently have on the GT. Also easier to have a full wheelset with a cassette so you don't need to swap it out each time. Note there are SRAM style XD hubs which aren't compatible with 10 spd systems if that's what you have.