Well Steve, you don't beat around the bush, and are letting the worms escape from the can. You asked how long it was before I was comfortable in all ranges, but what you really want to know is how long it will take you to reach that point. But maybe answering the question about me is the best way to estimate what you want to know.
I told you it isn't quick and dirty, right.
First, about me. I'm not a pro player or a particularly accomplished amateur. Like you I'm a comebacker after 40+years. Played up through high school and a bit in the Army.
Had to retire just before Covid and came across my old Conn Director and found I could still hit high C. I figured I used to know a good bit about trumpet operation (not to say playing), wondered if I might get proficient at it if I took it up again and got a decent instrument. Found a good deal on a Getzen Severinsen and set out on my mission.
I soon realized that too much of my playing involved lip clamping, overblowing and way too much MP pressure. Did a lot of Internet research and, after fighting my way through the BS and misinformation, reached the idea that there were more efficient ways to play. I set out to find someone actually teaching that and found Greg Spence's many rather energetic videos.
I established on my own that it was,indeed, possible to create the necessary vibrations by creating a small open aperture in the center of the lips and set the inner tissues of the lips vibrating by releasing air through the aperture. I could play a little that way but controlling pitch etc. was elusive.
I quit lip buzzing completely at that time and signed up for Windworks. Note: I did not have any performance obligations and still don't.
Greg had just put Windworks online at that time so it was very much still under development. He was available in a forum and by email and answered everyone's questions.
WW consists of many instructional videos and many custom exercises to teach his method. All this is pretty effective at teaching the basics. Progress is self directed.
There was a bit of a problem, though. The correct Embouchure is kind of tricky and it is hard to confirm on your own that you are doing it right. Also, inn its final form all pitch control is done by controlling the horizontal width of the aperture (opening in the center of the lips) . This requires very fine control that is done entirely within the mouthpiece cup and CANNOT BE SEEN. The only effective way to teach or confirm these aspect is by a knowledgeable instructor (Greg).
Periodic private lessons (by Zoom) was one (expensive) answer, but Greg had a better idea. About 2 years ago he instituted Sunday Masterclasses over Zoom. Every Sunday afternoon he makes himself available for 1-2 hours to answer questions, demonstrate things and even have individuals demonstrate their problems an spend time correcting them. BTW there is one session during US afternoon and one 12 hours earlier for europe.
Once individual personal guidance for no additional cost became available the WW program became much more effective. There are also ways to get a free private lesson or schedule a brief no-cost tuneup session with Greg.
Greg is always receptive to feedback during these sessions and incorporated many of those suggestions into the course (including several from me).
So to answer your question about my progress:
When I started WW I effectively had no comfortable range (maybe serviceable to high G or so. But,I totally quit playing the old way at that point.
You will not be able to do that because you will need to play the way you play now while gradually incorporating the new way, starting in the low range and gradually working your way up - always switching to the old way when necessary.
In the last couple of months I have become comfortable up to about high G and serviceable to about Bflat. But I am finally increasing range more rapidly.
If I started WW as it is now and I had not taken as much time off as I did (no gigs, remember) I would say 1.5 to 2 years would have gotten me to this point.
Put the back of your hand near your mouth.
Kiss the back of your hand gently.
Remove your hand, without moving your lips.
You have just formed the embouchure you would be playing on -- Mouth relaxed, lower lip rolled out slightly and protruding very slightly. Upper lip relaxed. NEVER roll either lip in.
Hold that Emb., take a deep breath then release air through the opening between your lips. You should get them to vibrate at a low frequency. If it doesn't work, increase the air release a bit (but NEVER blow.) Also you can try decreasing the size of the aperture a bit. You'll get it eventually.
You'll probably think "I can't possibly play this way". But you can.
I'd say that if you take advantage of masterclass sessions and book some kind of private time with Greg every six weeks or so , it might take six months to grasp the basic method and another year to get some kind of proficiency.
That's enough for now. If you need more info ask questions or maybe we could Zoom.
Greg