Going back to ship-config, the ship was overweight, and stuff had to be sold, and 'return' was blanked out; but when I tried to click on either 'sell' or 'store', it dropped me back to the main F3 menu. Is that what's supposed to happen?
No, that shouldn't be happening. The "Return" should be blanked out (to force you to do something about the weight), but that sounds like I've missed some condition somewhere. Can you check your latest.log file for any info that might help?
Here's the relevant bits:
00:50:29.427 [LogEvents]: Fer-De-Lance Carrier 4 13471 spawned at 112 km
00:50:42.441 [LogEvents]: Player gui screen will change from GUI_SCREEN_STATUS to GUI_SCREEN_EQUIP_SHIP
00:50:43.730 [LogEvents]: Player gui screen changed from GUI_SCREEN_STATUS to GUI_SCREEN_EQUIP_SHIP
00:50:54.297 [LogEvents]: Player ship got EQ_SHIPCONFIG
00:50:54.308 [LogEvents]: Player ship lost EQ_SHIPCONFIG
00:50:56.249 [LogEvents]: Player gui screen changed from GUI_SCREEN_EQUIP_SHIP to GUI_SCREEN_MISSION
00:50:56.424 [LogEvents]: Player bought EQ_SHIPCONFIG
00:51:06.749 [LogEvents]: Player gui screen will change from GUI_SCREEN_MISSION to GUI_SCREEN_EQUIP_SHIP
00:51:08.854 [LogEvents]: Player gui screen will change from GUI_SCREEN_EQUIP_SHIP to GUI_SCREEN_EQUIP_SHIP
00:51:09.707 [LogEvents]: Player mission screen ended
00:51:11.680 [LogEvents]: Player mission screen opportunity
00:51:17.945 [LogEvents]: Player gui screen changed from GUI_SCREEN_EQUIP_SHIP to GUI_SCREEN_OPTIONS
00:51:19.705 [exit.context]: Exiting: Exit Game selected on options screen.
00:51:19.706 [gameController.exitApp]: .GNUstepDefaults synchronized.
Closing log at 2018-02-26 00:51:19 -0500.
... It looks like "BountySystem_MostWanted 0.8" might be the culprit?
Is there any way of showing how much equipment space (and cargo-converted equipment space) is still available while in the main F3 menu
Unfortunately, no. The F3 screen doesn't have any way to add secondary info to it, like equipment space remaining. I added an F4 interface screen that lists all equipment items and the space/weight properties for each, and the Ship Comparison OXP will show the standard equipment space for each ship, but that's as far as I can go.
Edit to add: The one thing I can do on the F3 screen is to show a console message after each purchase, saying how much space is remaining. Would that do the trick, do you think?
If that's what I'm imagining it is, it could certainly help.
Is there a particular in-Ooniverse justification for the limit of converting 40 tons of cargo space for equipment?
Each ship has a different limit, but there is a maximum of 40t (which will only apply to larger ships, eg Anaconda). As for the reason for 40t, it was just designed as a limiter to avoid the "throw in everything plus the kitchen sink" (which was the whole point of the OXP in the first place). 40t seemed about right.
A lot of settings in Ship Config were guestimates only. Real-world physics and geometry don't play a big part in any of the calcs (which really applies to the rest of the game, too!).
Fair enough, though I'd be willing to debate with you about some possibilities for differences between pieces of equipment that are fairly solid lumps, like engines, and ones which are more diffuse across a ship, like armor; but without my Oolite running right now, I'm going to guess that you've already accounted for that in the differences between equipment-space-tonnage and weight-tonnage.
If a pilot picks the default set of gear, the ship is supposed to match the specs if the ShipConfig addon isn't installed, right?
Edit to add: The EquipmentSpecifications.ods file might be a little out of date. I'll look at getting an updated version out shortly.
Looking forward to it.