Some random thoughts on an interesting thread.
That colour shot looks like the balance weight and trim-tab are remnants of an overall rudder stripe color. Is that so, or was it an impression they wanted to give?
The doors
I always wondered about the gear door covers, especially when I was making model kits and couldn't get them to fit proper then!

My guess is that they weren't very accurate 'fit' on the 6th - 10th June, but after that they got 'neatened up' along with the rest of the stripe set. It's also not difficult to measure along the edge of the gear well where the paint demarcation changes and measure the same length onto the door cover - and that'd be accurate enough for the job. Didn't even need anything except, say a piece of string...
D-Dat stripeology
The D Day stripes were ordered as the risk of friendly fire over the air/land/sea concentration of 6th June in Normandy was infinitely greater than the risk of enemy surprise attacks. (Think about it - there were a lot of concentrated Allied forces in a small space, all twitchy; meanwhile we'd worked hard to send the Germans the wrong way or endeavoured to stop them turning up for the party.) As time went on into July, the use of camouflage from above made more sense as the allied forces thinned as they spread out and the Germans were more of a risk. So the 'half stripes' appeared when the top side stripes were cut back or taken off. It still made sense to have a good id from below, as the ground troops and navies tended to be trigger happy. As 1944 wore on, they were phased out in favour of no camouflage paint for speed, or full proper camou. Aircraft operating in inclement / night conditions had their white toned down, black left, and other extemporary mods were carried out.
I'm always amazed at how well air force aircraft followed painting instructions in the middle of moving wars...
Triv corner
And completely at a tangent, but keeps me amused: 'D Day' in France was 'J Jour'. The alliteration was more important than the letter.
The barber's red and white pole goes back to the mediaeval period when most people were illiterate and barbers cut up people, and pulled teeth, and didn't mess with hair. The red and white represent the blood and the bandage of robust surgery, and the pole went up outside the premises so people knew what you did. In that sense, it was working heraldry, and is essentially the same job as on this Mustang.
Finally, and Jack knows the details on this, but the P-40 under restoration here in Australia as 'Bonecrusher' (we'll leave ID arguments aside for the moment) was because the pilot was, IIRC, an osteopath!
Regards,