Thanks for the post andyst. I will try to answer your points.
It's true not everything in the guide is based on level 3. There are 2 goals to the guide:
(1) Help players who wants to stay lower level than their pp affords them.
(2) Help everyone get the most out of their current level - even if it is max level.
Level 3 is a terrible level to stay at, if you want to compete for pp. I do it for the challenge to see how far I can go with just 1 city. My goal is to see if I can stay in top 50 while reaching 5.763.973 pp (pp requirement for level 19 from level 3). I would say that is a reasonably hard but also rewarding challenge for someone who has no alts, have never feeded and never bought coins.
If I could do everything again on a new server, I would start by sticking to lvl 0 then 3 until I had all building upgrades. Then lvl 4, 7, 10 building full sub along the way before jumping 3 levels to next sub level. I would stay at level 10 because you only have to fill 4 warehouses to gain 64K pp/day from troops and you still get pp advantage when attacking higher level players. At level 13 you get 68k pp/day from building troops, but it costs more farming effort and you get less pp attacking higher level players. When a merge was announced, I would consider if it was worth it to level up to level 13, but I would never go above that even after merge. A level 10 or 13 has a seriously good chance of being no. 1 on any server.
The reason I can say this is because I have not yet finished an "attacking for pp" section to the guide, but in that part I will show why you have an extremely good advantage as a low level player when scouting and attacking targets. Quick point: Against a target 8 level higher, I can get 7,8k pp from 2.560 cav (starve size from a lvl 15 crop city) behind full level 10 turret wall if target has faster speed, simply by attacking with cav. Being no. 1 is not about having the biggest army, it is about attacking the smartest. Everyone trains troops all the time and most do it by large or max batch sizes. Those are your source of pp from attacking and when you do, you want the pp formula to work in your favor - hence you want to be 8 levels below your target, so e.g. 1 cav loss only costs you 0,8 pp.
Oh and since I dont buy coins, I never worry about warping for attack - but just at level 4, you could use your sub for attacking so the coin cost is half from level 3.
One last thing to point out is that you are not getting the max pp from your builds if you just go for 599 cav / 249 cat

I showed in the guide what the optimum troop composition was with/without vip. I have been getting questions in game on how to achieve optimum troop composition, so I will add to those sections to show practical application of the knowledge.
Quick method here: (non-vip)
1) right before you sleep, build 599 cav + 890 arcs. Then farm so you have full warehouse when you wake up.
2) Set alarm to when the cav finishes. Then build 599 new cav and farm to build 249 cats when the arcs finish.
3) Again set alarm for when cats finish, and build 249 cats.
Then set alarm for cavs and start calculating when you will go to sleep that night. Build a cav batch that will finish right before that sleep time.
When cats finish, build around 140 cats.
4) When cats finish, build small arc batch that will finish right before your sleep time.
5) repeat step 1
Keep suiciding the batches of troops you dont need as soon as they are finished so no one attacks and kills them.
important: When you start step 1, make sure you have close to 4200 manpower. Do not have more more than 5000 manpower, or you will lose pp due to reaching 6390 before build finishes. To reach 4200 you might have to build more cats one day until you are aligned.