I cant believe how much the wood has shrunk in this 30c heat.
Still, the tongue part is 3/8" long, so no actual gaps appeared, yet.
Thats why I was advised to use Featheredge (plus its too long for a single length) ....as long as you leave a good overhang.....I got 5" which is rarer than I expected and I needed about 6 lengths to finish it....had to wait 3 months....fortunately the gap was round the back where no-one could see.