There is no hard and fast rule about which size charts to apply for the ANTS trading. It is personal preference and your reading of the charts. Throughout the Forum, there are a few comments about this topic.
An excellent resource is the ANTSSYS YouTube channel. In some of the more recent webinars, Neil provides some great examples of how to modify the range bar sizes so as to achieve some "smoothing" of the charts and the relationship to the all-important 300EMA. Irrespective of whether you are trading on eSignal, the ANTSSYS Trading Platform ("ATP"), or any other platform, the recorded webinars on YouTube are very informative. You won't be wasting your time in viewing them.
I wish you well with your ANTS journey.