Hello and thank you for the questions

1) I cant say for sure this
2) The use of DB Cache usually solves these problems if something is slow
3) You can skip records and these things, but this is not recommended as it will skip the entire Vc

I see that you have tested various scenarios, but i cant give any 100% solution for this.
Are you able to contact me on skype perhaps? Lets start getting a solution or fix for this one
brorerikkotiranta

is my skype
Br, Bror-Erik