I have 19" CF5V's withNitto Invo 275/30 ZR19 (will be upgrade dto Michelin Pilot Sports after build/shakeout). I don't have any issue taking the nose off/on. I do have an interference issue with diffuser at full droop which I hope can be resolved with a little trimming of the diffuser.
Colin - do you have a side shot of your front clip mounted to the car, with the wheels sitting at ride height? Curious what your clearances are like between the tires and wheel well. I'm assuming it's contacting at the lower edge of the wheel well?