My take on the blood issue is as follows;
Laws on Blood in the OT invariably revolved around the proper disposal of blood. Also, being a symbol of the life that a creature once enjoyed only had significance when that life had expired . . . ie; poured out on the ground symbolically returning the life to God.
To illustrate . . . if an Israelite under law were to syphon collectible amounts of blood from his animals while still preserving them alive . . . for the purpose of an offering . . . what value would that blood have? . . . none at all . . . the "life" it represented would still be in the animal . . . walking the earth . . .alive. Check all the scriptures on blood . . . you will see this understanding coming through time after time via the scriptures.
The implications for using transfused blood are simple and obvious . . . donated human blood from a living donor has no spiritual significance at all . . . it does not symbolise the life from whence it came . . for the life WT claims it symbolises remains in the donor.
WT has it all wrong at first base . . . as you can see it makes all this childish nonsense about blood fractions etc etc (ad nauseum) totally redundant.
The Mosaic law required violators who consumed blood in, say an emergency, to simply wash thier garments and remain ceremonially unclean till the evening. It was/is a symbolic reminder of who is the author and owner of life . . . not some "magic fluid" of itself.
The only area for misconception of this understanding was the decision handed down in Acts 15. The situation here was simply a concession to the jews (in return for allowing Gentiles to keep thier foreskins) for the sake of peace and is in fact an outdated imposition by the older men in keeping with the Law of Moses which the Jews found almost impossible to let go of entirely . . . check the context thoroughly . . . it is a concession and by no means meant to be binding on Christians till the end of time.
The early Christians had the same penchant for rules . . . for they were babes as to matters of conscience. I'm sure you can think of other examples where this situation created problems.
The whole principle of respect for blood was to engender respect for life . . . a purpose which the WT has sucessfully managed to spin through 180 degrees so as to perpetrate unnecessary slaughter.
Hope this makes sense . . . but I've yet to see this understanding successfully challenged . . . run with it for a while and see where you go with it.