Can you have the store print a formula-label for that color and post it here?

I wouldn't even sell you the paint unless you're gonna use a gray-primer!!!
* Since you've taken-down paper, rinse it well...and I mean 2 or 3 times!!
* My 1st choice for the primer would be Zinsser's Cover-Stain Oil, or Odorless Oil. I'd tint these to medium gray.
* 2nd choice is a grayed-down latex stain-blocker like Zinsser's 123.

THE IDEAL METHOD...1 coat of Gardz, followed by a Gray 123 primecoat. You can tint Gardz, but it'll dry faster without colorant.

Ignore the "Flat" fans! That kind of Red in a Flat would be disastrous in a Bath!
(unless you NEVER touch the walls, or moisture magically stays away from the wall.....)

If it's the "daily" shower area, I hope you choose a Satin. Yes, it's got a sheen, but will wear very well in a moist room. Plus, that color will have a high colorant-load, meaning the film itself is vulnerable to moisture in lower sheens.

Faron

Use Gardz as a primer because you stripped wallpaper from the walls and Gardz will lock down any residual paste that you may have missed. Gardz is clear, but it is an excellent sealer as well. When applying the Gardz, you want to use a very short nap roller sleeve like 1/4" and be careful not to apply too much. It's really like applying water to the walls (it's that loose bodied). One dip goes a long way. Topcoat with Aura in eggshell or semi-gloss. The reason Aura is a good choice here is because it covers better than any other paint available on the market so you do not need to prime with a grey primer. In the days before Aura was available, we used to prime with grey and then perhaps still need to do 3-5 more coats. Aura will cover in two coats 99 percent of the time. You don't want to use flat because it is a room with moisture that will be collecting on the walls. For the trim, you will need a normal acrylic primer like Zinnser 123 or BM's Fresh Start, then topcoat with Aura or even Waterborne Satin Impervo would be fine as well...anything high quality and acrylic with some sheen.

Can we use the gray primer under our trim or will that effect that color?

Can we use the gray primer under our trim or will that effect that color?

If you are doing two coats with high grade/quality paint, the gray underneath wouldn't scare me.

But if you were my client we'd test it first.

Try it with the gray and if after it's thoroughly dried you don't like it you know you need a different color primer.

And if you have not purchased paint yet I agree with PG Aura is the best choice for red for all the reasons he stated.

I've never spec'd more than Aura matte for kitchens and bathrooms. So far so good. The matte does have a lil slip or gloss to it - it's not a flat finish.

Don't use grey primer on the trim if you are painting with some cream color topcoat. The reason you would use the grey is because red covers grey easier than white. In the case of a white or light colored topcoat, grey would be more difficult to cover. You want to stay light so that you end up applying fewer coats.

You're cool to use Gray-primer under ANY color (except real bright/vivid colors), even Whites/Ivories, etc.

If you're putting paint on correctly, and not too thin, you're golden. Whites have the best opacity anyway.

Faron

Maybe I am misunderstanding, but we are talking about priming the trim grey? The trim that you are planning to paint some creamy color? I guess it's okay, but I just don't see why you would do this. Some of those creamy colors cover horribly. These are among the worst covering colors ever chosen. If you are starting with a grey base, there is a good chance it could take 2-3 additional coats of paint to cover that grey up. So, why would we do that? Just because we have the grey primer on hand and you don't want to buy some white primer? If that is the case, just skip the primer, sand the trim really well first and then just paint with the topcoat.