I have to admit I am confused Phil !!, I've just looked at Oddley's info again and it appears that the dry rub contains exactly the same amount of cure ingredients as the injection with only the water (100Mls) being the difference (and of course the insoluble bits), therefore the total cure amount is split 50%/50%, but you mention 1 litre of water, I can't see 1ltr being part of the recipe/cure??
I never was very good at maths but I have done a spreadsheet calculator to help me
Ped