2-3 is fine. 4 and more at the same time then the fields may have a weaker effect. Depends on your energy system though. The more expanded and wider flowing it is, then the more energy your energy system will be able to take in.
2-3 is fine. 4 and more at the same time then the fields may have a weaker effect. Depends on your energy system though. The more expanded and wider flowing it is, then the more energy your energy system will be able to take in.