Have no idea about the print capacity but know that Selenium toner last a long time, i will let the tone tell me when it is time to make some new.
I had a chance to use the Ilford/Harman Selenium toner the other night and actually did a comparison with KRST. Both dilluted 1:9 Did not find any difference on the Ilford FB WT paper but perhaps a slight difference on the JandC Nuance. KRST seems to tone a little bit more light brownish than the Harman and perhaps a slightly less pronounced midt tone effect which i like. Also did a test on Forte Polywarmtone FB Mat surface and there was no difference. Everything was toned for 2.5 minutes and the temperature was 21C.
jan