Okay, I honestly can't remember: Do you need to keep xeno teams on worlds with ruins after they've been completely mapped out to find technology, or do the engineers find that along with recovering installations?
The engineers find it. Assign commanders with xenology bonuses to the engineers to give them a better chance.
If I remember correctly, it dictates the maximum number of turns to be taken, so if you set it to 5 and click 1 Day, it will keep going until you get an interrupt or 5 days have passed, whichever comes first.
Actually it's the minimum number of turns, not maximum. What it does it completely ignore all interrupts for the specified time. There isn't a way to specify a number of auto turns as far as I know, but you can just turn it on and turn it off again when you're ready. Auto turns will stop when an interrupt happens.
Bit of an AAR (minor spoilers in the description of the ship I guess, but it was just precursors):
I just battled it out with four 7550 ton precursor ships packing lots of fast anti-ship missiles. 7500 speed, 40 ECM, and their missiles were going over 40,000km/s. My ships were starting tech (all tech on them from a 500 mil pop start, roughly 105000 tech points went into them). 3000 km/s speed, basic size 4 wh 4 missiles with 60km range. My AMMs were 1.2m range. I went in with 20 ships: fifteen 4000 ton 3000km/s destroyers armed with 5 size 4 launchers each with a loadout of 49 missiles, and five 4000 ton 3000 km/s point defense ships armed with 12 size 1 launchers with a loadout of 204 1.2m km range anti missiles. I'm 3 years in and the 20 ships was me building military ships constantly the entire time, and with only 20 labs I didn't get any significant tech done so they were all still top of the line.
I managed to approach them to within my missile range of 60m km (I had a wp where they were when I saw them as they killed my survey vessel) before activating my sensors. They turned out to be 55m km away, and I was able to shoot through their ECM thanks to my over ranged 2.25 size 94.6km fire control. I fired off two full 75 missile volleys at each target, leaving me with 9 missiles in reserve on each ship.
Their missiles arrived first and my anti missiles proved woefully ineffective, only managing to hit about 17% of their missiles. Firing 4 per missile with a second volley for some of them managed to keep most of them off, with only a few leaking through - but I quickly ran out of anti-missiles and started losing ships. Each ship meant 40 less missiles headed at the target, since they didn't have active sensors and without guidance they self destructed. I lost 4 ships before my missiles even started making contact, with a fifth crippled but still in possession of its fire control - leaving me with 110 missiles going for each target. The first two waves hit and managed to barely destroy ship #1, then more of theirs hit outright destroyed two of my ships. Ship #2 was disabled by the two waves that hit it, then I lost a 7th ship to more enemy missiles before my 5th and 6th volleys made it to target #3 - heavily damaging it, but still leaving it effective. I immediately fired another volley at this one, hoping to survive long enough for them to make their targets. An eighth ship of mine was heavily battered by their next wave, but with two ships disabled half their missiles seem to have self destructed and weren't quite so lethal anymore.
My last missile launches managed to mostly cripple #4 due to a secondary explosion, but shortly after I lost another ship that was already damaged by earlier leakage through my PD. The third enemy ship then turned and started running, but my last volley fired managed to reach it and finish it off.
I then had 5 of my missile destroyers with 20 missiles between them, 5 escorts with empty magazines, and two crippled ships with no ability to continue fighting. One of the damaged ships was limping away at 500km/s, so I fired 12 at it and 8 at the other and went to get the life pods. My last missiles barely destroyed both the remaining ships.
The aftermath has 8 of my ships as wrecks, 1 of them crippled to the point that it can't move but it's doing damage control on an engine so hopefully that works, another damaged down to 1 remaining engine slowly limping home, 2 with minor internal damage, and 3 with just armor damage from a few missiles getting through. My five PD ships are completely untouched, I guess the enemy must target the ships with bigger active sensors (they only have missile sensors). Total casualties were about 2600 crewmen and 7 of the commanding officers (two made it to escape pods out of the 8 wrecks, the badly crippled one died to a bridge hit).
That was a pretty epic battle. If I had known they would kick my ass so much with only 4 ships I would have waited a few years and brought 40 instead of 20. After the PD ships ran out of missiles each volley of theirs was wiping out a ship, and they were steadily coming in 4 packs of 8 every 30 seconds. I think they just targeted my destroyers from top to bottom of the TG and fired a volley at each, then repeated. My AMMs kept them at bay for a good many volleys, and when they ran out it was the ships right in the middle of my TG that started going down. I lost ships 6-13, and 14-15 were the crippled ones. Ships 1-2 have slight internal damage, and 3-5 are the ones with only armor hits. Without the point defense it would have just ended with all of my ships dropping one by one before any of my missiles even reached them.