What kind of sight should I put on my Tippman x7?

Question

I have customized my x7 to look like a M4 ( 6 position stock, 14" barrel and vortex muzzle brake) but i still have the factory sights on it, i was considering an open red dot sight like the reflex, but i dont think ill be able to see through it with my mask on. Thanks for any feedback.