+1

I noticed that when one drags poles along a blueprint with poles, poles get built at the positions they are at in the blueprint instead of the default mode (that either maxes out the distance between poles or attempts to power all buildings, or both).

That's amazing!

But then I used upgrade ...

In Signal Selector in any context, allow (optionally) to specify a pair of symbols as a signal. It could be thought of as a symbol with a subscript. For example, signals could be [oil] or [1], [steam] or [E] (currently available), or [oil_1] and [steam_E] (new) if seen as subscripted, or ([oil], [1 ...