As I have a bespoke tuner fitted to my heavy gun it was very enlightening to hear the comments of serious testing as mentioned in the podcast as opposed to reading other shooters views on websites like 6BR regarding how tuners work etc.
I know that you need to find the most accurate charge weight first and cartridge overall length etc. Then moving the tuner to fine tune which might improve group sizes (or not) and their positioning, but I think that in the real world there are other influences (wind strength being the main one for me) to give me confidence to say my tuner has made it more accurate.
As I do not have the laboratory facilities to prove it conclusively works and need my money for other things (women, holidays etc) than bullets, powder etc it can stay on the barrel and locked in one position unless I decide to do a non analytical test for a bit of fun in a tunnel range.
After all it's just a hobby really!