The reason i fit in groups is that if one fails, the others will work until you can fix the broken one plus the reflectors do not really focus the light so pointing in the general direction will cover all that area .
You will like these lights for economy. If i were using for a garden party, i would use the gentle warm white. For super brightness, the cool or day white. The ribbon type with 300 leds only last around 3 years due to sunlight attacking the outer waterproof coating. They are 12 volt on solar power and safe enough as long as a fuse is fitted.
My experiments have been over a few years now to find the optimum for my use. I now have LED lighting inside the house for every room
For an uncluttered look, the 30 watt will usually be enough on its own but i have not tried these for reliability. I would expect it to be good if it has a single plate LED and not one made up of many on one circuit board.