Batfink, yes, the weave is easier with one or two attackers but the original was also designed for two sections flying abeam each other and the entire division would fly the weave. It also worked against superior numbers. Also, you're right that it's dangerous for the fighter being attacked but then it's a defensive maneuver designed against the bandit attacking the section from their high six. Here's a good pic of it.
The weave is really fairly simple for anyone comfortable flying a fighter but it does take some practice and a modicum of SA. Blukitty's right, you probably wouldn't want to count on a nugget to do this with. Many don't understand the objective which is for the free fighter to get a quick kill or they're no good at high angle deflection shots, reversals and sustained turns.
It builds on what should be a normal reaction for any section to a stern attack...both fighters turn into each other. This gives the free fighter the quickest shot at the attacker. When the two fighters cross after about 90 deg of turn it's simply a matter of both reversing their turns to repeat the maneuver and set up the scissors. It does take some patience, timing and more importantly discipline.
I'd say trying to stay within D400 is not setting up the right geometry unless you're already slow or doing a break turn and bleeding which is not the intent (unless of course you're getting your bellybutton shot off). It also makes it harder than it needs to be. If you're too close you won't have gotten enough turn before you cross and you probably won't get the forward quarter shot unless you bleed and you'll probably end up with a more difficult 90deg deflection shot. Another problem with being too close is it's harder to determine who the enemy is attacking.
The fighters should be at about a turn radius of each other so that would be anywhere between D600 and D800 (even further for poor turners and at high altitude) depending on the plane and they should stay close to corner velocity for best turn rate. Of course, as things slow down (which they will after two or three scissors) the whole affair gets tighter but by then you should have dealt with the first attacker or he should have blown through. In cases where there are two attackers, the weave complicates the second attacker's problem a bit because both fighters are out of phase but he can't be ignored. One weave and a quick kill on his lead should make him think twice about continuing the engagement. Or, if each bandit takes a fighter and attempts to follow them through the weave each fighter should ideally be able to gain forward quarter attacks in each bandit.