I never use hoses, they always have problems. Frequently even regular bottles have icing problems at the nozzles.

I prefer one hard bottle and one soft, each about 500-600ml. The hard bottle usually goes in the crampon pouch of the pack, accessible without removing the pack. I like having the one hard bottle for aid stations in longer races, it’s much easier to fill up on the fly, especially if you ever hand it to an aid station volunteer.

The 500-600ml soft bottle goes nicely inside of my skin suit. For a ~3hr race, I’ll usually consume most of it before the end of the first hour, so it’s really not a lot to have against your chest. Then it stays nice and warm, and also closer to your center of gravity. After emptying it, sometimes I’ll throw it into the pack, especially say during a downhill to uphill transition where taking the pack is more likely. But if an empty soft bottle stays in your chest pockets, that isn’t a big deal either.

Yes, I wouldn’t use a bike bottle. They tend to leak. Check out the Hydraflask bottles. They’re great.

It’s also worth measuring how much fluid you actually need. Weigh yourself before and after a 1h simulation (at race pace, wearing (not much for) race clothing, at race temps, etc). Then plan on 2-3% as an acceptable level of dehydration.

You’ll probably need to take something for a 3h race, but under 2h, maybe nothing if you can dial clothing with temperature and not sweat much at race pace.

The 600ml version of this has been perfect for me:
https://skimo.co/ski-trab-race-bottle
Maybe during some warmer races I might be getting a bit dehydrated at the end, but I suspect that’s offset by not carrying around excessive water at the beginning of the race.
I also try to make sure I’m sufficiently hydrated *before* the race, which is easy to overlook with all the other last-minute preparations.