I couldn't tell from the information in console, the "you've successfully pasted the structure" hadn't shown for a while. I phrased it as "trying to spawn" because there were less than the specified amount of bases on the map and it'd been much longer than the usual time it takes to spawn a new one.
Regarding specs, I'd agree but I didn't have this issue with larger maps with more bases and reduced my plugin count around the same time when I moved to the smaller maps (I was on a performance improving kick). CopyPaste is on default settings and the two fields you mention are set as described. I've been running Raidable Bases for a long while, so the machine has proven it can handle it.
The junk I was finding in the spawns was weird, player stuff (TCs and boxes) just floating in the air. I set these to false and I'm not getting that any more.
"Do Not Destroy Player Built Deployables": false,
"Do Not Destroy Player Built Structures": false,
Thanks for the info, I'm going back to larger maps next wipe. A few plugins have been behaving weird since I moved to 3.5k.