"[Request] Advice for mid-level (25+) strategy"

#PokemonGO: About a month ago my girlfriend got me into Pokemon Go, and I've been playing and enjoying the hell out of it. It's surprising on how much more walks and bike rides I go now, and I get to meet and talk to a lot of cool people on the trails.Since my goal was to catch up quickly to her level, the initial strategy was easy: Catch any Pidgey I encounter, and pretty catch anything else as well, and once I have enough candy to evolve ~70 Pokemon, pop a lucky egg and go to town. And whatever you do, hold on to your star dust and "rare" Pokemon candy for the higher levels.The gym meta in my area has a pretty high turnover, meaning that no gym stays with the same team for long. Sometimes I can snatch an open slot, or prestige a low level gym and collect 10 coins. But now that I'm level 25, I feel I can get bolder and try to get two or three gyms at a time before cashing in.BUT, I have a hard time finding a comprehensive guide for the higher levels. I read a lot on here and found out that you get more prestige by using attackers that are half the CP of the defenders. Is that true? What makes a good attacking line-up? Who are good defenders that I should put into gyms after I open a slot?Mostly I accept the suggested attacking line-up, but I have the suspicion that that's not a great idea usually. Usually I have trouble against high CP Blisseys (timing out). I tried to Google, but there's just so much conflicting information out there. An army of Parasects and Raticates with Solar Beam? Primeapes and Machamps with Close Combat? All of the above?And should I start spending my star dust on the more useful high IV pokemons that I have now, or should I still wait? What would be good candidates to start powering up?My apologies if this isn't the right sub to ask more open ended questions like this. Most of the other threads seem to discuss very specific topics... via /r/TheSilphRoad http://ift.tt/2qaRorC