Should the virus antigens be modified-live--the ones that multiply in the host--or "killed"?
When I started out in practice, I used MLVs--the stronger the better, I thought. But as I grew wary of the whole notion of vaccines, MLVs began to seem particularly risky. Though they confer more sustained antibody protection than killed vaccines, their challenge to the immune system imposes too great a strain. Now, after all I've seen in the way of adverse reactions to vaccines, it scares me to put any potentially live infectious agent into the body. Does that mean "killed" vaccines are preferable? By process of elimination, yes. But this is hardly to say that "killed" vaccines are always harmless. Because they're less virulent than MLVs, they're also less effective. As a result, manufacturers routinely boost them with powerful adjuvants, or additives, to provoke a more sustained immune response. But these adjuvants can also cause adverse effects. My preference, overall, is still to give no vaccines.

Should the same dose size of vaccine be given to a chihuahua as to a Saint Bernard?
If you're not familiar with veterinary science, you're probably thinking, "Gee, that's an easy one--of course not." Guess what? That is the way vaccines are administered. And to most veterinarians (and all drug companies), "one dose fits all" in such common practice that it's simply never questioned. Press the point and you'll get a vague rap about the vaccine antigens being such minuscule agents in an animal's bloodstream that dose size is of no concern. Ergo, a one-pound Chihuahua puppy and a 15--pound full-grown Saint Bernard both get I-CC vaccine doses that contain not only viral agents but various chemicals used to inactivate the pathogens, plus the chemical "vehicle" used to carry the organism into the bloodstream, plus a preservative to keep the whole toxic mix potent, plus a colored dye agent (typically red) to make it look pretty as it enters the body.