Well the actual numbers you put are not that important as much as their relative sizes, the exact numbers tend to depend too much on your current stats. But here's some general rules to follow:
If you can afford the cost to your mana regen, haste is your best throughput stat. So you'd want to give a higher weight to it, say 0.7 vs 0.5 or 0.4 for the others, with 1 being spellpower.
Now for crit vs mastery, they are of equal importance about when your crit percent is 8-10% ahead of your heal mastery percent, when all buffs are factored in. So if you hae 15% crit percent and 18% mastery percent, you want more crit vs mastery. If you are at 20% crit and 12% mastery you're about right and they are of equal weight. If you are at 25% crit and only 12% mastery, then you'd want more mastery.
My guess is that unless you were really favoring crit before, your crit would not be that far ahead of your mastery and you'd probably want to be getting more crit.
Intellect tends to come to around 1.3 or 1.4.
I'd say if you want a hybrid spec, aim for the first decent haste breakpoint for holy, then try to keep your crit and mastery percents about the same. mastery tends to be a bit better than crit for holy, and a bit worse than crit for disc, keeping them close would be my course of action if I was playing both specs.