Splash of fish sauce works instead of dashi, or skip it. Can also use chicken stock instead of water for more flavor.
The chinasichuan link is a good reference. Start with the lower liquid proportion and increase as you get comfortable (more liquid yields a more delicate custard, but is trickier).
For 1 egg, I set the first timer for 7 mins and start checking - you want a slight jiggle like quiche. Add a minute at a time and keep an eye on it, it goes fast at the end.
And even if it gets overcooked (bubbles in custard, liquid separates) it still tastes good, so mistakes are edible 
