If I were alone it wouldn't be a problem, but since I'm going with my partner who has been preparing for approx. 3 months building fitness, and it would be her first Triglav ascent, sleeping on a bench doesn't appeal to her

One day is still too much for the first time, in my opinion.
I've booked accommodation at Valentin Stanič hut, morning from Krma to Planika and Triglav, descent via Kredarica to Stanič for overnight and Sunday descent.
I hope for nice weather already on Saturday, crowds but expected in August