Rob,
I have done some printing on a couple of different canvases using my 24" printer and dye inks. Yes, I'm a glutton for punishment but I do double coat them with sealant. The answer to your question differs with the texture of the canvas and the amount of detail in your subject. I have printed at 100ppi and I like the results with portraits, even when there is fine hair and eyelash detail. I don't, however, think the results would be as satisfying with highly detailed landscapes. Coarse weave canvas too is less demanding of fine image resolution than some of the finer examples. I use Qimage to resize my files and believe it has a lot to do with the quality of the results. I also think that the clean files I get from my 8.2Mb files also has an impact here, but I don't really want to get into brand arguements. Sufficient to say that noise free files print better, even on coarse surfaces, and especially when they are being subject to large scale interpolation. Regards,
Gary.