For your polar alignment, the Polar Align feature in your C11 will help you get it roughly right but drift alignment is the best (takes practice to get faster at it - I have the luxury of a fixed setup in a dome). This will control declination drift so a guidescope mainly works on the RA and hence longer exposures become more practical. Your balance shouldn't change your alignment but does affect tracking so it is important (changes again when you have a hyperstar). Flats will be very important with the hyperstar as a lot of vignetting but you can image so many objects in one night you will be very excited. If you have any problems getting the 2ry mirror out to place your hyperstar, let me know and I can give you some tips or Dean at Starizona can. Bahtinov mask I find is best used by taking images and examining them zoomed in or in live view zoomed in to really nail it (remember to take it off when you start imaging, not that I have ever done this
). Good luck