Hello thanks for for the article, it's very interesting.
About your experience, what is the best over-discharge and over-charge voltage cut-off to increase the battery life ?
According to this table from batteryuniversity.com , if we cut at 4.10v instead of 4.2v we already gain lot of cycle from 300–500 to 600–1,000 it is not negligible.
Of course per stage haha sorry my mistake 
I have question about TP5000/TP5100, there is not problem for charging 1S6P battery pack with cells in parrallel ? If i understand well If charging at 4.2V 2A each cell will receive 0.333 A right? Total charging time = 3400/330 = 10.3 hours ?
Yes of course , but I find that you learn a lot of things to do it yourself and it allows you to have something flexible and above all sustainable and from an ecological point of view, if something is not right you can fix it without having to throw everything away.
Oh wow, you learn me something
Thanks for this remark.
If i use battery holder, What will be the impact of the resistance in term of loss in %? It's better to soldering ?