Support weapons

It's in game. Simply "set support" on a base to determine how long it would normally take for one base to support another. The timer is clearly shown. Maximum time is like 10 minutes in nearly all possible scenarios.

Think it's a bit more complicated then that, but the comment is helpful. The big question is: IF I have set support on base a from base b, and base a is attacked, does that mean there is a delay in the support on base a "unlocking" and supporting base a? If I have set support on base a from base b, does the support from base a ever "unlock" and support another base under attack (I think not). IF not, then best NOT to set your support on other bases, since you never know what base is going to come under attack.

All supports will defend any and all ally bases that come under attack, so long as those ally bases are within range of support weapon type. If a dozen bases are within range with each other and all 12 come under attack, then all 12 bases would eventually have 12 supports each (typically 8-10 min). The only thing presetting a support does is eliminate the need for that support to help that base. Typically, this is done when a particular base is holding a key position.

8 to 10 minutes. since with most attacks you are dead within 2 runs, doesn't seem like setting supports would help much

Depends. Bases within 2-4 clicks will support nearby bases within 2-4 minutes. Several factors are in play here and every battle (and world) are different. Level 65 offense vs level 65 defense between top tier alliances with 4-8 support weapons is going to hurt significantly.

The point of PVP is to cause the attacker as much difficulty as possible (typically in the form of repair time), but still allow the attacker the opportunity to win, always. Except in the case of support weapons. If the attacker cannot kill a base in 2 hits and there are enough support weapons nearby, the attacker will need to first clear all support bases before attacking their primary target.