[LintMan]

That's a great idea about putting the queues on hold rather than mothballing the bases.

About planet building - The all-asteroid systems I see on my current map all seem to have about 3-5 huge/large fields and another 2 or so medium fields, plus some small and tiny ones. The all-asteroid systems aren't all that common, but my (large) empire contains at least 4 systems of that sort very suitable for planet building, but I guess everyones mileage may vary on that.

As far as getting random world type and atmosphere, by the time you're up to the planet-building techs, you've most likely gotten all the colonization techs, and also have researched Atmosphere Converter III. So within 30 turns of so of creating the planets you'll have the right atmosphere. (Sounds slow, but it takes that long to build a ringworld anyway!). Or if you wanted to, you could bring along a planet-destroyer ship and try again for a habitable planet next turn.

Benefits to planet building:
- free planets! You pay the maint cost of your planet-builder ship(s), but that's it - no large space-yard-ship fleet, no cable/plating/gen bases to build.
- fast - each planet builder ship can build a planet every turn if there's enough asteroid fields around.
- much quicker growth if you have replication centers. If you have 5 built planets, they can grow at 200mil (5 * 40mil) per turn total, whereas a ring/sphereworld would only grow at 40mil/turn.
- equivalent of greater numbers of facilities. It only takes 2 huge built planets to equal the facils of a ringworld, or 4 to equal a sphereworld, one asteroid system can far outstrip a sphereworld for facility capacity.
- quicker buildup - since you have a production queue for every built planet, you can fill up all your planets' facility slots more quickly than you could fill the 50/100 facils using the single queue in a ring/sphereworld. Similarly, if you put a shipyard on each built planet, you'd have a far greater overall ship production capacity than even a fully populated sphereworld.

Negatives:
- planet values are random instead of maxed out, so some planets might not be suitable for resource production.
- spread-out planets are tougher to defend than a single ring/sphereworld.
- if you don't have any asteroid systems or regular systems with huge/large asteroids, building planets is less beneficial.