sbelyaer,
I currently use Ilford MG IV RC Deluxe and have had very nice results with Kodak rapid selenium at 1:10 for 5-10 minutes of toning time and toner temperature 70-75 deg F. My results are most noticeable from zones II through VI, with the zones IV/V showing the most response to a slight "color" change, that I can only describe as a definite "cooling" effect when compared to an untoned print. The lower zones II/III, mostly just get slightly deeper as you observed on your prints. Below zone I, there is no change in color for this paper, at least at 1:10 anyway.
Chuck