I agree with Ronjohn7779, if your using bubblebags, then you can use different strains, the different charcteristics of that strain will be carried through to the hash. It's only really practical if you have a decent amount of each type.
It depends if your using buds, or if your just using leaf.
If you're using buds, then I would dry it completely till it's bone dry, then break it up into very small pieces- don't grind it up; as the plant particles may get through into your hash bags.
If your just using leaf and little scraggly bottom buds, then i would freeze them while they are still wet, and use it when wet. You will get less contaminants in your hash than if you dry the leaf first.
The reason why there is a difference depending on what you use, is because if your using buds, you are using something which has a much higher rate of crystals to plant material, where as if your using leaf, you'll be using something which has a much lower rate of crystals to plant material, and therefore there is more chance of contamination from plant particles, so to curb this slight drop in quality use wet leaf.
Ideally you want a strain which produces a lot of crystals, such as white widdow, most of the strains from DNA genetics, like LA Confidential, Kushberry, Sharksbreath etc.
I found White Russian to produced a shit load of really, really, strong bubble hash, but I found it a very strong smoke too. So strong it almost ruined smoking Skunk for me
If your using leaf then try getting a strain which packs on the crystals, but one that also has a high leaf to calyx ratio.
If your using buds then you will find that you will get good results what ever, so either just pick your fave strain so you can try it in hash form. Or just pick one of the white strains, like White widow, or White Russian, so you get the best yield for your efforts.
What CannaSeur said about live hash and dead hash is exactly right; although I have used bubblebags with dry stuff and wet stuff, leaf and buds; and have not really noticed a difference in the finished product. You must dry the crystals after extraction anyway, whether you break them up and let them dry over a few days, or if you just remove the water straight away by hand pressing straight after extraction (the longer you take to dry the crystals, the smoother the smoke will be) If your using buds, it seems like you get a bit more yield if they are bone dry when you do the extracting.
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All use of bubblebags occurred in the Netherlands, where use of cannabis is not classed as breaking the law. I do not advocate breaking the law in which ever country you may be from, this is purely informative.