Pretty much my experiences what they've posted
We 'perfected' the empty as we progressed.
To start we had hopper keys so could get an idea how close to the £125 full it was without even spending a single £1 or sometimes even ordering drinks
Travelled here, there and everywhere in search of these and in UK founds LOADS, Stafford, Shrewsbury and Chester being our main 'Gold Mines' lol. Once a week, usually after a weekend fill from what we referred to as the 'pay day addicts'
Watching your vid, I don't think it ever lost as much as your short sample, seriously, 4,5,6,7,8,9 would very rarely lose and after 5-6 JP's we also leart that 3 & 10 would do you, unless you now applied the reverse to those numbers also.
Another thing we found was to get rid of the change numbers as early as possible, having a '2' on one reel and say a '4' on another, we'd change the '4' most times it would drop a '1' for a no lose and quite often the '2' for the pair match.
I don't think many 'normal' players ever JP'ed these as the streak kicked in 7/10 after the 1st Jackpot.
Best I recall was one in a Weatherspoons which was really playing up, £15 in for a JP and taking the lot back to get the next one, all of a sudden it repeated and repeated and repeated, gosh knows how many times but it went totally empty and we even had a small IOU from there (which we've still not been to collect to this day
)