Both / all those types of utilities are effectively useless for predicting what will be the best channel to use in actual use.
I used to use inssider (and other similar forgettable tools) and it only added time to getting a wireless network optimized and running smoothly and most of the time, it did not correlate to what it indicated at all.
The most straightforward method is:
Use a wired computer or NAS (not a USB connected drive) to transfer a large 1GB (or larger) file to a wireless laptop computer (preferably plugged in or at least in the 'high performance' power mode) in various locations of the area to be covered (make a note to locate and orient it exactly the same for each iteration of the tests you'll do). Note the time, speed and consistency of the transfer (both from the wired device and back to it).
I also use
Ookla and / or
dslreports speedtests to measure and confirm the ISP maximum speeds and also their consistency too.
Finally, I quickly browse to different sites on the 'net to get a feel for the latency each channel offers.
All three of these tests are equally important and should be done for each channel tested on each band for each specific location in the area covered by WiFi.
Only use channels 1, 6 or 11 (and 13 if your country laws allows it) to test the 2.4GHz band. Use every available channel in the 5GHz band (as they do not overlap like the 2.4GHz band channels do) when doing your testing.
After setting a new control channel on the router, reboot it and wait at least two minutes for it to settle before running your tests. I would also recommend to reboot the laptop you are testing with too. (Yes, this is a time consuming process).
You will quickly find that only 1 or 2 channels on each band give the best throughput and lowest latency along with the greatest range.
On the 2.4GHz band, using channels other than 1, 6 or 11 (or 13) may give you a better result. But you are causing interference for everyone else on the higher and lower channels from the one you selected (again; because the channels in the 2.4GHz band overlap).
As you can see from the above, what a utility like inssider or anything similar indicates has nothing to do with what is required to find the optimal channel for each band of a WiFi router in a specific environment.
On the contrary, it only gets in the way and makes more work and takes more time for little to no benefit (except maybe a bit of information).
In addition, during my testing (above) with a utility like inssider running, the throughput, consistency and latency were usually far worse than when the utility was not running. This was my final indicator that the benefits were few and far between for this type of utility. I haven't used one since. And have missed the 'information' it offered even less.