I have now abandoned (aka, eaten) 100% of the varieties I used to grow that produced only bulbils.
In 2016 I purchased and traded for 5 varieties that are known to have produced TGS. Last year I did get a few TGS off one of them, but then proceeded to lose it among the discarded stems. Mainly last year was increasing stock for replanting anyway, and my TGS was only a halfhearted effort. I will be trying it with the vase method use for flower stalks.
I now have
NOVO TROITSK (USDA W6 26171)
CHESKOK RED (aka SHVELISI or USDA W6 35657)
NAVISTAR
CHIMYAN (W6 46684)
PSKEM RIVER - the one least likely to produced TGS.