@ObiRonMoldy I spent about 9 years with my instructor who was a Korean Grandmaster in Tang Soo Do and also held that rank in Kung Fu. He studied at the Shaolin Temple in Pu San... but due to politics in the TSD Federation he didn't talk as much about the kung fu. Frequently we learned techniques without knowing exactly where they came from. The only forms that I know apparently came from the Plum Blossom Fist although I've seen my instructor perform several others such as an eagle style form.

The version of Tang Soo Do we learned... I haven't seen any other schools with similar technique. Tang Soo Do is supposed to be 40% Kung Fu from the Tang Dynasty... but the way most schools teach it... there's no soft style in it.
My Kwan Jang Nim's personal preference was Chinese hand technique combined with Korean kicking technique.

After I developed Cushing's Syndrome (which damaged most of my joints) I tended to favor Chinese hand technique as well... the fluid motions put less stress on my joints. But my hand technique is hodge podge... some of the things I learned from the form Sang Po (no idea how to spell that because I've never seen it written) and other bits of things I learned from other Kung Fu sources, other stuff I extrapolated from what I knew... and some stuff I just made up

One of my old students from the 90's is now teaching a couple of my students from 2013. That's kinda cool. Not as cool as me continuing to teach but, can't have everything
Mostly my art like my bloodline is kind of a dead end.

@ObiRonMoldy
From what I've seen Hwarang Do is a very interesting art.
Tang Soo Do is supposed to come from Soo Bahk Do and Tae Kyon (a Korean art unrelated to Tae Kwon Do). Tae Kyon is supposed to be a lost art... apparently practiced by criminals and such. TSD is also supposed to be 30% Northern Kung Fu and 10% Southern. I have no idea of what comes from where.
Mostly TSD is kinda a confluence of Korean, Japanese, and Chinese techniques. All of our forms are the same as Shotokan.. but that's just the patterns.

Hwarang Do... is that related to the Society of the Hwarang?
The latter was supposed to be kind of a Korean equivalent of King Arthur's Knights of the Round Table.

@ObiRonMoldy Even though we were a very small school... I think it was 1982 but Hwang Kee (the founder of TSD) came to visit our school. Black Belt magazine was there to cover it. I was only a green belt at the time. I was always getting into trouble so I stayed away from the school that day. But I got to see my friend's pics in a national magazine.

@ObiRonMoldy From what I can tell for the most part TSD has fallen into a sorry state. Two major TSD federations appear to have entirely sold out. I've seen videos with multiple people wearing an actual master belt that I would not promote to green belt. I only promoted 4 people to black belt over 20 years of teaching. (Midnight blue belt actually... TSD doesn't use a black belt.)
I looked up some videos of Hwarang Do forms (kinda tricky because TKD has a form called Hwa Rang.) I saw one master doing a beautiful form that wrapped soft (but not weak) flowing movements around precise hardstyle Korean movements. That's close to the "evolution" of my personal style. If I were a bit healthier I'd like to learn that form.
And then as you might expect I saw some demos that looked like TKD with some vague approximation of kung fu tacked on. Some people really don't get that the fluid movements aren't weak. And they're not just performed with the hands but with the whole body. Grace is an important consideration, but it's not everything.
I don't really know any really good TSD schools anymore. There is one about 20 miles from here... the instructor has a lot of power and focus, but the version of TSD he's teaching is nearly Japanese. The stances and hand techniques are wrong. With that said the instructor is a good teacher and he is producing good students. I just don't think they're really TSD students. At the other extreme is people who teach TSD such that it's no different from Tae Kwon Do. There are huge differences between the two.
Sorry, I'm a Technique Snob.
Hey I spent almost 9 years getting screamed at... I wanna believe that wasn't in vain

@ObiRonMoldy Does your son still practice?

@ObiRonMoldy If possible encourage him to maintain his flexibility... it should help him in any other athletic endeavors. I read a study that said that 90% of all sports related injuries are a result of inadequate flexibility.

I was playing basketball at the Holy Spirit Church gym. Someone had spilled some water on the floor around half-court I hit it at nearly a full sprint... and I fell into full split. When I got up uninjured I think someone said... "it's a miracle." No, I was a red belt