Either option will work - but your workflow will be easier with a single file.
bear in mind that it doesnt have to be exactly the same pixel size... it could be smaller so long as its the same ratio (and an even number)
Just watch the data rate on a single large file.
Only way to find out is to TEST.
Base spec should do it fine...
or if you have the budget, the base spec with the top spec graphics card.
Try and borrow one to test first if you're worried...
Don't rely on other peoples test results.
S