I
sn't it better to use a 'picture' of what the runway looks like at the different turn points to judge when to turn.
Yes and no.
Differing widths and lengths between runways will have even a moderately experienced pilot (including myself) fooled at times. Although, the more exposure to this earlier on the better. Still, I don't think there is anything wrong with using known points for a turn when learning what a high, normal, and low approach look like for a given field.
It's also very easy to say all circuits should be flown within gliding distance, and, without a doubt, this should be used whenever practical. But, there are times when it just ain't the case.
The only issue I see here is the airspeed (or, more importantly, energy) management and steep(ish) turn close to the ground.
Regardless, it was an EXCELLENT outcome!