Fastest/Lightest 24" (507 BSD) tires

[Wunder]

I'm trying to make my son's 24" CX bike a bit more efficient for some on road rides this summer and looking at tire options. It is a 24" (507mm) mountain bike style rim, and can clear up to a 40mm tire. Options in this size are limited and I'm wondering if there are any options I'm missing.

Ideally, I'd like something in a slick/semi slick with fairly soft sidewalls and if possible a folding bead. Not sure if this exists. I've checked both Bike24 and Bike Tires Direct and this is what I've found (I have all these). These will be run with tubes (planning TPU for weight).

Schwalbe CX Comp - 24 x 1.75 - These look to roll fairly well on all surfaces. and I had them on the bike the last several months. However, they are HEAVY (558 grams each), max out the clearances, and I'm hoping to do better.

https://www.schwalbetires.com/CX-Comp-11100126.01

Schwalbe CX Pro - 24 x 1.35 - came with the bike and are fairly light at 371g but not the best on road tread pattern, also looking to save for fall CX season as replacements do not seem to be available (only 26" still sold).

https://www.schwalbetires.com/CX-Pro-11100185.02

Kenda Happy Medium - 24 x 1.125 (labeled 507-32 but measure more like 29) - I installed these yesterday and they are what I was planning to use. 362 grams, run narrow, smooth center section. However, the sidewalls of these are really stiff, only 30TPI, and they might even be undersized for these rims (had to inflate multiple times to get them to sit right on the bead shelf, not sure they ever caught the hooks).

https://www.biketiresdirect.com/prod...yclocross-tire

Any other options? Ideally, I'd get something like a Panaracer Pasela or Continental Ultrasport but those don't seem made in 507 BSD.