quick SEV gameplay questions

[Suicide Junkie]

As I said, one turn's worth means that you really don't know what you want.
You're asking for a semi-random number of mines?

Why not just queue up 100 mines (max deployable) and then your facilities, or some fraction of that depending on how dangerous you feel the territory is?

Or you could put 10 mines, then a mineral miner, repeat.
That way your colony's protection increases proportional to how developed it is.

Perhaps you want enough mines to blow up two of those planet-glassing scout ships the enemy has flitting around?

You just need to decide