Hi John,
hhmmm. That sound like there would be loads of different configurations of Macs, which does not seem to be so reading a tech specs of the hardware. I believe there been only 2 models with 2 variants each and effective changes between MBP of 13-14 have not been significant.
Mojave & High Sierra are not available in AppStore/iTunes. I know that support pages - they are pure waist of time.
Generally speaking with new soft either they are more effective or they drain more of the resources. The needs or usages of computers are not changing with upgrade of OS. They tend to stay pretty much the same and either there is generally positive or negative impact or maybe no impact. Or impact in some areas. That kind of sharing, I believe, might be helpful.
Thank you for your guide. On my Mac are theater shows, using a specific sensors working with specific applications and software. There is no x64 options, so unless you would like to send me couple of thousand € for remaking everything once again, your answer is useless.
I have to use computers professionally and I have to use Mac. I am no fan boy of the Mac thing and Apple is also famous for liquidating usefulness of older models by overburdening them with new OS.
So I am sorry John, but I found your reply pretty condescending. I do not need to read how I should not be afraid to instal brand new x64 OS with low tolerance to another software on 6 years old laptop.