It’s going to be hot shortly. And obviously need to find some solution for running sessions of 1.5-3 hours.
Does anyone has some recommendation for a hot weather? (about 28-33 Celsius)
My preferences are for hydration backpack instead of bottles to avoid a need to stop and refill.
Looked at Nathan VaporKrar but after a couple of reviews I figured out it would be too hot and sweet accumulating.
Any feedback about Nathan VaporAir would be appreciated as well 
Hubby got the Salomon ADV skin 12 recently and likes it. Two bottles in the pockets in front and space for a bladder in the back (and other stuff too). He hasn’t had a chance to try it out in the heat yet.
That or maybe this one for better ventilation (but no option to carry a bladder)
https://www.salomon.com/en-us/shop/product/s-lab-sense-2-set-20.html#color=20101
Personally, the two included flasks would be fine for me for long runs, especially if I plan my routes to go past fountains or gas stations.
I used to run in similar conditions, tried quite a few options that I already owned or borrowed, and didn’t get on very well with any of the packs that involved a bladder on the back. Just got very sweaty and uncomfortable for me. YMMV. I ended up with a cheapish random brand waist belt off Amazon that held 2 x 300ml bottles on the hips, and left my upper body to sweat freely, plus no chafing from the straps. My long runs had a couple of places I could refill so that worked for me. I like the look of the vest options posted above that only have a mesh on the back and hold bottles on the front, if I needed more capacity I think I’d go for one of those ahead of a bladder.