update:
I think the mod in the video was the UDT-L after all. it does screw up to the vamo but the whole thread does not screw in. I've got mine working but you have to be really gentle with the threads. currently vaping a stardust (yes, i know) on 2 18650 efest 2000mah cells. definitely a home use vape this, it's way too tall to be at all portable and i would not like to drop it or give it a knock that stresses the thread where the vamo sections join to the UDT-L sections. It does sit in my hand better though, doesn't seem to be as prone to slipping out as the plain vamo does - the extra length means any angle at all forces it into your hand so it doesn't slip so easily
It could just be me but i feel like the vamo, even single cell mode, vapes better at the same voltage than my previous ego twist. I think probably because of the PWM switching of the vamo. More taste with less burn and more vapour. It feels even slightly better than that, with 2 cells in series
I used a spacer for my battery spring, works fine although i think a 2c fuse would have done the same job
trying to get a spare vamo extension section now so i can keep the mod on this vamo and give the UDT-L its longer section back to make a portable 18350 mod to go with the ego adaptor and phoenix atty i have on the slow boat
for those of you with a vamo and a UDT-L i have a feeling that adding the short section of the UDT to the vamo would allow the use of 2x18500 in the vamo whilst still keeping the UDT-L free as a 18350 portable