I recommend MyTailor. I've ordered from them several times and have referred several friends who have all be pleased.
You are in LA. Joe has his offices in So Cal. I would arrange for an in-person meeting with him to measure you and to select fabrics. As good as any companies on-line experience can be, it can't replace seeing and touching the fabrics or discussing fine details of fit with a tailor in person.
With Joe, for my first order, I selected 3 fabrics, he made up one, sent it too me to be sure of the fit. He was visiting the area so I wore it to our next appt and he suggested a few very minor changes to it before making up the final shirts. They followed a few weeks later.
Joe will adjust the fit, collar and cuffs within an 1/8th of an inch. So, wear your favorite fitting shirt, tell him what you like or want and I'm sure you will be pleased.
Another benefit from working with MyTailor is he can do shirts as low as $65 and up to $500 each, with the only difference being buttons and fabric.
I get mostly Thomas Mason fabrics, MOP buttons, soft cutaway collar shirts and they average around $160 each. I wanted a certain shade of pink. Thomas Mason didn't have it and it wound up being about $79 simply because of the source of the fabric. Yet the fabric feels and looks deluxe. Some of the better TM fabrics really look expensive and for under $200 you can get a custom shirt that rivals any of the major brands RTW in dept stores like Neimans for $395+.
Beware. Lots of guys who post on SF don't have experience with premium fabrics or true custom shirts. They write glowing reviews of MTM shirt companies that use good but not excellent fabrics and cuts that are nothing more than simple variations on a standard template.