I’d echo comments about being hard to seat and I had to use CO2. I ran 2.5 minions dual ply on Flow rims in the alps last year. I also used them with the rim strips in addition to yellow tape for added security and tighter fit to inflate.
I gave mine a testing on a few DH days and they were fine before using in the Alps and they were ok for most of the week, but I did burp the front tyre on one day, so I always had a nagging doubt after that and stuck in more psi to compensate.
I would say it’s a bit of a risk without rim strips and if you lose enough pressure (burp) then you won’t get it back on the rim without a CO2 cartridge, or sticking a tube in.
Since mine were knackered after last years trip I’m now running proper UST Maxxis 2.5s and they go up a treat (trackpump and without rimstrips). They feel up to the job of DH too.
Best advice is to give it a try, but give them a proper pasting to be 100% confident before using them on an event. You’ll be mighty annoyed if they fail on you, for the sake of running tubes.