Live in Vermont and there is a lot of talk about Conan.
I hear that it came from the Vermont Pub and Brewery ( source local Guru).
That the Alchemist uses the same strain for up to 16 generations. Hence, the variability in flavors from Peach to Grapefruit ( lower Attenuation, more grapefruit flavor).
My usual and very successful culture method for this hearty strain:
3 cans of HT: pour into a glass ( yes its brew time, not taste time!) 3/4 of a can that has been upright and chilled to 42 degrees, and decant the remaining beers with the top of the can sterilized into a 1.040 DME light solution ( that had been boiled and chilled to about room temp) in a 2 liter flask. Fill to about 1200 cc shake and cover with sterilized porous foil and wait a few days and pitch. You may also step up the DME concentration especially if you want more cells, etc. With this method I usually get the FG to about 1.016 to 1.014.
Sign Post Brewing had the best HT Clone that I could find but is now off the internet:
Here is my suggestions for good Clone:
https://www.brewtoad.com/recipes/heady-topper-clone-8
Yes, what we call Conan is actually VPB-1188 that Kimmich was given by Greg Noonan. There are multiple ways to gather enough yeast to make a batch. In my case, heady is difficult to come by, so I could only culture from a single can. I used multiple steps to achieve this successfully. It sounds like your method should work, but at an estimated 2 billion cells per can, 1200 ml is quite a bit. I would still recommend a step procedure to grow them properly and avoid stress failures.
Oh, and the signpost recipe is the same one from the first post of the massive "heady topper can you clone it?" thread here on HBT.