HPHT vs CVD

I'm in the market for an emerald cut diamond between 10-20 carats and I'm having a hard time finding companies that sell HPHT lab stones. Does anyone have any companies or vendors that sell HPHT? Do you think they matter or make a difference vs CVD labs? Also, please share your color grade and ratio for any large emerald stones, I'm wanting to do a platinum band and I'm trying to decide which color grade looks best as some say D and E can be too harsh with emeralds.