Hi Anton,
Yes for your first requirement if you are copying one more set of planning area and which in turn contains all the key figures, CVCs etc. for same time horizon then memory occupied in Live cache will also increase proportionally (approx.)
For your second requirement, I cant specifically say if doubling the LC memory will result in faster data load - obviously if LC is healthy then jobs and proceses tend to run faster. Also the speed observed by users while using various functions interactively depends on various underlying technical parameters too like Network etc. So as you said LC memory and processing speed may not be directly proportional but you can notice some improvement.
Hope it helps.
Regards,
Alok
