My Snails Have Arrived Early! What Do I Do ... ?

So this is the big weekend.

I've been keeping the tank cycle going in readiness for planting and stocking this weekend..

My plants were ordered last week and will arrive tomorrow.

So, tomorrow I'll be removing at least 90% of the Nitrate-packed tap water.
Planting out (91 plants - that will take a while!)
Pumping in 50L of RO water I've been storing (in a cool dark place) for just under a week.
Pumping in 50L of tap water.
Measuring the hardness using my TDS Meter and recording this reading as my baseline - the ppm reading I will be aiming for at each water change.

On Saturday morning I'm going to my LFS to get 6 Tiger Barbs, my first tank inhabitants.

And now to the dilemma with my snails.

I ordered 10 Malaysian Trumpet snails yesterday and they were supposed to be delivered on Monday.
My wife just contacted me at work to let me know that the snails were delivered about an hour ago.

I don't want to put them in the tank tonight because I'm due to add another 1ppm of Ammonia.
Also I don't want them burying themselves in the substrate before I've planted; I don't want to accidentally crush them when I'm locating the plants.

I can't put them in the kid's tank upstairs as they'll bury themselves and I'll likely lose some...

What can I do? I only need them to live outside of my aquarium until Saturday now.

I'm thinking I can perhaps fill a container with aquarium water from the upstairs tank and seal it ... ?

Any other ideas?

Thanks Sue.

Of course, I only need to keep them until tomorrow night after I've finished planting.  :

I must be able to find a tub with a lid ...

That's where you want them to be.

And you had value for money with all those extra snails