Hello Umblah, welome to Susan's!
Yeah I'll go easy on ya.

And first, congratulations on a half year with your HRT prescription! Time flies when you're having fun - my HRT experience has been awesome. I am MtF from the Seattle area.
I have not heard of Dr. Nicholas Kim from Minnesota.
For GCS, it's quite possible a surgeon may have their own requirements but I don't think there is a standard waiting period for HRT. WPATH requirements (followed by US insurance companies) require one year Real Life Experience (living in gender role) before GCS. I had my in-person surgical evaluation 3 months after starting HRT, with GCS surgery 6 months after starting HRT. The surgeon was mainly interested in checking overall health and genital hair removal. Hair has a random growth pattern and may require 6 - 12 months of electrolysis in the surgical site area (or laser, although I consider laser less permanent for many people). Some surgeons do not require hair removal and scrape hair follicles by spending additional time during surgery. I wanted to minimize the risk of hair growing back and do everything possible to reduce time under anesthesia, so I went the electrolysis route. Depending on which surgeon you use, hair removal may require time and planning.
The other timing issue depends on which surgeon you choose. The best-known GCS surgeons in the US currently have a waiting list typically two to three years. There are exceptions - I went to a surgeon who had worked along side one of the top names for a couple years. I was able to get in fairly fast but her waiting list has already grown since then.
Having just had this surgery less than two months ago (mine went great, no complications) I completely agree with your statement this isn't something to skimp on, you only have one shot at it.
Since this was your first post I'll include information to help with navigation and provide site guidelines.
Things that you should read
Umblah, when you get a chance it would be great if you can introduce yourself in the
Introductions Forum.
I'm glad to see you here, and best wishes on your GCS decision.
Kendra