Peter, there can be a nice difference when using warming filters (or any filters for that matter) with colour negative film and wet printing.
Assuming your printing situation is that you have achieved good colour balance in the darkroom, filters do help in certain situations.
If you are doing a landscape where significant parts of the picture are in open shade, whilst other equally important sections are in full sun, then to help matters in the darkroom and to kill the cold bluish open shadow areas, I add an 81A or an 81C. My 81A is 200K warmer and decreases exposure by 1/3 of a stop. My 81C is 400K warmer and decreases exposure by 2/3 of a stop.
Basically you can just do straight printing without worrying very much about changing filtration to offset the bluish cast. They aren't very noticeable on the direct sunlight sections of the picture, but they certainly do remove the bluish tinge.
I find that I nearly always use the 81C.
The 81C with colour neg film will also make great outdoor portraits with pale white skin. The times I have used that filter on portraits, the sitters have been quite enthusiastic about the results.
Mick.