I regularly use Ilford standard MG RC paper, and their warmtone, both in standard MG developer. There is a very subtle difference. I think it's unlikely that you would see a print on the wall made on warmtone and recognise it as such. It's only when you put it next to one made on standard MG paper that you can see the difference in a slightly cream paper base and slightly warmer blacks. However, I've never been a great fan of cooler prints so I love it, in fact it's my favourite paper, especially in a pearl finish. The other advantage is that it selenium tones nicely, really warming up if you want it to, while the standard RC in selenium cools down slightly and get's a slightly higher D-Max. I've never played with warmtone developers so don't know how they would affect the final print.
I change image color with toning not with paper selection.
I can get a nice neutral warm from MGIV with sulphide toningand a cooler look with selenium.
Well I do both. The first point is really relevant - there is only a slight difference between most WT papers, Ilford WT included, and neutral papers when they are untoned. But they respond very, very differently to toning.
I tone virtually all of my prints, neutral and cool ones in selenium because they generally cool a bit, lose the ugly green tinge that they all seem to have and that you may not notice until you tone it away and then you can't fail to notice forever after, and gain D-max, albeit sometimes subtly. Warm tone papers (for me that's Ilford MGWT FB now) I develop in WT developer and typically tone in brown toner, though it can also take on a very appealing warmth in selenium where neutral papers cool, as the previous poster said. This is a more reddish warmth than the more yellow/brown of brown or sepia toners.
The differences untoned are really only clearly apparent side by side, but the different response to toners is drastic.
No experience with RC WT papers, sorry. The MGIV regular RC seemed to be a pretty close match, tonality wise, for the previous MGIV FB. I've not used the new neutral or cool FB papers yet but plan to when I get lower on my stock of Adox MCC 110.