Regarding the buffer size. I run at 32 and a 5 millisecond round yep without issues but my projects are pretty basic, with relatively low track counts. I’ve seen several people in this thread (who are far more knowledgeable than me) say they run at 64, is 64 good enough to record vocals or acoustic guitars with a few inserts?
Whether it’s good enough is a question you’ll have to answer.
If you’re monitoring direct when you record the vocals and acoustic guitars, then the buffer size doesn’t matter.
If you’re monitoring through insert plugins on the computer though, you’ll want to minimize latency. Turn the buffer size down as low as you can without overloading your cpu.
What matters is the round trip latency (in ms). What latency you get from a 64 sample buffer depends on your interface, its ASIO driver and your chosen sample rate.
Absolutely down to interface and drivers. I get the latency you get with buffers at 128 with my RME Babyface pro fs. Lowest I use is 64.