Those specs are good. 1000 mcd (
Milli-candela) = 1 lumen. so 16-20 Lumens per bulb. I think, someone correct me if I'm wrong. Anyway they are bright. Hurt my eyes bright. even with sun glasses on I don't like to look right at them long.
Like Coca-cola say's the straw hat gives 160 degrees. Normally they are a bit pointy, and much lower brightness (in my experience) like 14000mcd. These ones are more rounded, but really low profile, The bit the light comes from is only just under the surface.
The one's I linked to are a little on the blue side. Much like a fluorescent or compact florescent.
If you look at the specs on the page, you will see warm white will only give 13,000 - 16,000 mcd. which is still pretty decent light. I like the full white myself. I know a lot of people prefer the warmer white. I would use warm white in a bedroom, or tv room, but definitely bright white in kitchen/shop/lab. the photon wavelength of pure white light alter brain chemistry, making you more alert and "awake"
Re sticking 1000 individually to the ceiling. Lol! don't do that. you'll get rsi.For 12 v you would be putting them in strings of 3 in series with 83-100 ohm resistor. you can then put them in parallel to form blocks. at 10 ft I'd go for around 30 per bunch, and spread the angle a bit to give more than 160 degrees. Still a lot of soldering, but it's cheap.
Again Coca-cola gives good advice. bigger ones use more power and put out more light. you might also consider something like
this They are more expensive, and use 5x the power, but they put out 5x the light as well. so fair trade of, about the same value. a slightly smaller angle is the only downer. Just be careful there. Some 10mm LED's are identical to the 5mm ones inside, just different casing. Could be a trap for beginners.
I'd still go for the 5mm myself, as they would cast less shadows, with there being so many of them. Although if time and risk of rsi are more of a concern, the 8mm every time. the warm white 8mm look pretty decent too. Have a look around and see what you find. I have purchased from that shop a few times. They are ok. Good prices and good quality in my experience. Although postage from China is really slow. 2-4 weeks is fast. sometimes 8-10 weeks.