:
If you're running scientists, you're cutting into a whip cycle or taking citizens off mines. There isn't a magic economy. You're not going to see a drasticimprovement by going with "SE" (a convoluted term) unless you are otherwise overbuilding cottage improvements in war games.
With that being said, spec cities convert intomore rapidly, but with planning ahead on which cities will produce units the difference in hammer potential isn't anywhere NEAR what "SE" (again, ridiculous terminology that means different things even within this thread) advocates imply.
Frankly, for struggling with warmongering on noble it's probably way too soon to start thinking about overarching "economies". Specialize on a per-city basis, improve tile micro, tech priority, and diplomacy (to avoid dogpiles), and go from there. The vast majority of your cities are going to be hammer cities for early conquest.
All QFT too. At this point I don't know why I'm always agreeing with TMIT so much... kinda spooky. At any rate, my further advice on military:
Whipping is also overrated, particulary if you don't have a good reason for it. I know it doesn't sound like it's very solid but I can advise to avoid whipping in general unless you really know what you're doing. It's good around the axe stage, and alright of course if you desperately need units; after that whipping can be very costly to your population, and in the long run it's often even less production. Most importantly, though, it's a short window that players often try to extend by going overaggressive on the whip.
Once you can draft, you should almost never whip units again. Just no, don't even consider it as a strategy, not even in peacetime. Natural disclaimer though - there are a few exceptions to be clear - if you're not running another civic, sure, whip captured city pop that would starve, or maybe if you really, really need a ship or something crazy. And of course if you're still running slavery and need buildings in new cities that's alright, but whipping is a much worse conversion than drafting. I just can't say how many times I see players still whipping when they shouldn't be - even without Globe Theatre still cycle the draft through your cities instead.
Lastly, late game there's a choice for production that far beats out anything CE or SE as most players understand them. Workshops (SP + Caste) are basically overpowered and you should build them wherever you need production - I usually find myself building them in almost every captured city, pretty much over anything that isn't a resource/village/town. Workshopping over farms also gives more production than engineers or any other specialists will.