if you are thinking of building your own 1911 their are thousands of build logs and youtubes that go over the process and where to get parts. as for dimensions try this: drafting!
As for Rock Island/Taurus/Tisas,etc depends on what variant and feature(s) the manufacturer offers. Reviews and details of these 1911s are all over the interwebs.
Good choice on the Defender. As for grips you could look at VZ, LOK, Wilson, or wonder through Brownells until you find something you like. As for cleaning, it is my EDC so I like to keep it clean. i field strip after every range trip, and do a full tear down and put it in the ultra sonic about once every 4 months
Even better. I'll take a look at that. Could I just do the polishing with some Mothers polish? I have some already since I did the 10 cent trigger job on my Glock 21.
I agree with starting with a good beginners book. That way you get the process down and what each step accomplishes and pick up on some terminology. I started with this one: https://www.amazon.com/dp/148207379X/ref=cm_sw_r_other_awd_37qvwb1ADM4YJ
You can also Google and look on YouTube for steps for reloading. The more you read from different sources, the more you pick up on.
I get what you mean by not reading what you see on the Internet, but I think that needs clarification. Most powder manufacturers publish their manuals online and those are safe to use. I'd rather go with those than some book that who knows how old it is. Just don't go by some guys load that he posts online. Always start with the minimum load listed in the manual and work your way up.
As far as equipment, everybody's situation is different. How many calibers do you plan on shooting? Roughly how many rounds will you be reloading? Do you have a hard budget?
If you're just reloading for 45 ACP, it probably doesn't make sense financially to get a super nice progressive press. Handgun cartridges are pretty easy to do and you can pump them out pretty quickly if you get something like a turret press, which is much cheaper. I would avoid a traditional single stage press unless you have a really small budget and/or plan on reloading very little.
Also, check out /r/reloading
Edit: full disclaimer I haven't reloaded for 45 ACP yet. Actually just got my first 1911 today. I'll break the gun in with a case of factory ammo then start reloading it. I do have a lot of experience reloading multiple other pistol cartridges though and one rifle cartridge.