I always had bad contacts at the head of the light... this was on 3xC3 the case. What could be a sign of longer threads, is the little gap between battery tube and head. I have sworn to myself to never buy UFs any more, where I don't have reviews to check for build quality on the main body, being the guinea pig on UFs is a pain. And even if there are good reviews, you might get something totally different with the next batch... how many different UF C3 are there? ... 10, 20... ?
I think the logos on UF depend on which day of week we have... Mondays it's TLTRAFIRE... because the logomaker partied to much on the weekend. You don't need someone else to worsen the quality, UF can do this themselves. Think of it as UltraLottery. You might get the best flashlight there is, or a doorstop.
Don't know of one - there is a referral programme but i have no idea how it works. If I did, I'd give you my link to use. But you would probably rather that you got the discount instead of me.....
Maybe a white wall beamshot next to the G2 on 14500 and AA for starters, if you own a smooth white wall. My white walls all have slight Orange Peel. In German it is called 'Rauhfaser' ... don't know the English word for it .... is it 'ingrain wallpaper' ?: