Risking being a pest:
1) People talk about unhappiness being a problem at higher levels-- but you get tax money. Has anyone figured-out the optimum in trade-off of squares dedicated to "Crowd Pleasers" versus population generated taxes. This would be without any Wonders dedicated to keeping the Rabble happy.
Are you referring to actual population increasing structures, ie farms? The top end for that comes early, as higher populations are harder and harder to keep happy. It's non-linear, so 16b people are not simple 1/2 as happy as 8b people. I'm sure others will give you a more precise answer, but you'll find out quickly that you don't want to push your populations too high.
I did answer a question about the optimum number of farm+morale vs economic buildings. Here is my reply. It breaks down how many stock markets you need to make it profitable to use from 1 to 4 squares for farm+morale buildings.
2) If you run a Trade route to a safe trading partner, can you run the route through multiple Starbases for multiple Tarrifs, or is it one and done.
You can run it through as many starbases as you can fit, adding the bonus for each additional starbase.
3) If you have two special squares for manufacturing etc on one planet does it make sense to use one for an assisting improvement (ie, Fusion) ? Or a Capitol improvement?
Manufacturing bonus squares don't help the %bonus improvements. Don't use them for power plants, man. capitals, etc.
4) The Dread Lords are a strange phenom. They showed-up in my present game. I fill the planet with spies and kill-off the the DL's unarmed Scout. They keep rebuilding (slowly) the scout. They lost control of the Galaxy because they're dumb. Do they ever try to clear-out the spies? Or stop producing scouts? Where is the Dread in Dread Lords.
The Dread Lords seem dumb because, quite frankly, they are. Their RaceConfig.xml entry is missing the code that lets them use maximum AI ability and CPU power. This is something I fixed in my mod.
5) I got two Rangers in my present game. I'm about to quite the game because I could create a fleet that would usually not exist until the end of the game. Yet when the AI gets these ships, they don't seem to use them well. I saw one CIV surrender with a Ranger in a previous game. What is the opinion of the Gal Civ Community on these ships showing up?
Don't have much for you here, sorry. I've noticed that the AI can fail to use freebie type ships - those that either pop up through events or are given to them. I also wouldn't expect the AI to realize that it has the premier warships in the galaxy and go on a rampage with them. The AI just isn't capable of that.
Thanks for the info on switching the personality types. It's a better game. And because the other Civ's are progressing better, the Torian aren't as annoying-- so far. I ran a successful freeze-out strategy on their trying to grab colonies. And that's fun.
Changing the personality types is just one step in making Twilight a fully enjoyable experience. You really need to either fix the TechTrees yourself or run a mod that does it for you. Several races have serious problems with research due to rampant typos, omissions, and blatant errors in their TechTrees. As a new player, I can understand that you may not want to deal with mods, but you will be very happy that you did. If you're interested, may I recommend . . .
Tolmekian's TechTree fix - My mod. Fixes the TechTrees and also many other problems with starbase modules, planetary improvements, UP votes, and other things. Current version 2.0, with 2.1 to be released shortly. Pretty much preserves the game while, in my opinion, improving it. It may be a mod, but it's not like you're playing a different game.
Good luck, and have fun!