Hey, I recently played a 90 world impossible vs 3 enemies that I won. I also play highest difficulty most of the times, but I usually tend to screw up one side of the games and end up restarting. Balance and micro management is very important.
I did not have the clans, so I made a team with DeVatos and Javat for economy and Rychart for the RP/EP boost for advancing faster and making treaties faster. I would probably chose Mok to replace Javat or Rychart for stable alliances or trade alliances late game.
What I do is focus on economy. The map allowed me to not worry about early alien rushes, so I more or less just expanded as much as I could. I tried to get my research to the same number as my population with lvl 1 spice dens(very cheap: 5/research point) and use FDFs for EP and TP(if you fill the pop slot and with the TP you can get the FDF to pay for itself). I just fill with those after maxing my minerals.
I try to rush transporter ships, colony 2 and then mines up to 3 if time allows. Exchange 1,3 and 3 and palace 2/3 are very important objectives early on for the research boost and for the economy they provide. Afterwards I go for factory 2, orbital FDF and orbital platform(these are more mid-game after I have a solid economy,some defense and 9 or more colonies). I would get colony 3 somewhere before the orbital unless I need them because of population growth and lack of quality.
I tend to scout the planets around the ones I want to colonize and start researching and producing ships around the time when an alien takes one of those worlds.
If the AI tends to rush on that specific map, I would have a few fighters around in key points. It's important to mention that I usually play on this specific map which allows me to expand to about 20 systems. that's usually the point where the enemy has taken the rest of the map and I'm on the defense. As soon as I get a decent economy and the basic invasion ships(I make custom ones with heavy troops and highest armor i can get into them) I start taking worlds. I continue advancing my ships as soon as I get factory 4.
Ships and fights:
I usually have WW II guns and pirate crews on lvl 6, fast reactor 7(or 9, i forgot) fighters with max attack.
For defense and scouting, full evasion cheap ships.
Support, multi repair or refuel ships with maxed ranged attack and missile spread for attack and heal when needed(my fighters sometimes get hit because i'm lazy or unlucky). Late game i don't take any repair on my fighters.
I usually keep my defense closest to the enemy. retreat if needed so that the evasion ship is always the one that gets fired to. have 2 of those for safety. I position my fighters 1 unit away form the next target.
The sequence is advance, fire, fire, reposition. this way, my fighters should always be out of range. in late game fights, i can clear fleets with just 4-5 ships.
You can also bulk up a fighter and have a healer behind. I never tested that, but it might work if the evasion strategy seems like too big of an exploit to you.
Cadar is very interesting because one can build early alliances.
I'm not sure if the wording is the best in this post, but I hope I got my ideas across. The ideas might not be the best, but they worked for me. Let me know if I am doing something wrong.