About the opfire rule, there's an idea came to my mind right after a shower yesterday
I know it may be impractical or difficult to do so, but I'm still gonna bring it up. If it's not a viable way, perhaps you can get some other ideas to perfect WinSP from that.
Let's come to it in WinSP rules. The core of the matter is that you could only order one single unit to shoot at another single unit at a time, but then you get multiple shot. So how about this:
You make your units select their targets first by "T" key. Then press a new function key to activate all the attacks simultaneously, and the opfires would drop on the attackers randomly, or according to some simple rules.