As far as I know, the rules don't have any particular requirements w.r.t. wind flags (though I admit I am lazy and have not looked it up before typing this!)
It is pretty standard to have flags every 100m or 100y. It is nice if there is a row of flags on the left of the range as well as on the right.
If you can't have flags every 100m, try to have (in order of importance) one on the 685y firing line, one about halfway down, and one near the targets.
How "open" is your range? (a field, or a slot in the woods?) What direction does it face? If you can only have one row of wind flags, and if you have a choice, they should be put on the upwind side.
Some flags are made of very lightweight nylon (e.g. the military ones are), others are made of very heavy cotton (Bisley style). They are generally in a "pennant" shape, at about 1:3 ratio (width:length to tip). Sometime the flags used for 1000y+ shooting are larger than the ones used for 600y, though that's more of a "nice to have".
People express very strong preferences (!) about whether heavy or light flags are "correct", the truth is they both have their plusses and minuses. The very light flags are much more sensitive, but they tend to "peg" by the time the wind reaches 10mph. The very heavy flags might move very little if any (especially if wet with dew in the morning) until a few MPH is blowing, but can be "read" to well over 15MPH, and in larger sizes to 25MPH (if correctly strung).
The flags needn't be at exactly bullet height, but they shouldn't be too close to the ground otherwise they are in "quieter" air.
Budweiser360 I am curious, do you know what range that photo is from?
