Blood meal is about 13% nitrogen. I would suggest that you not put out more blood meal than you would a 13-0-0 fertilizer.

Well, I wouldn't know a 13-0-0 fertilizer if it bit me in the behind. Nor would I know when and when not to apply it.

I garden only with compost, GCM, Soybean meal, some bone meal, and a little blood meal, with excellent results.

I've never been quite sure about how much nitrogen is okay around flowing plants, since I believe it encourages foliage?
It's all very confusing :) Things like: 15lb per 1000 sq ft is a strange direction when one is dealing with small beds of many different compositions.

Is there any sort of eyeball method or rule of thumb when using blood meal?

There is no really good way to know how much Nitrogen is too much because it depends on how active a Soil Food Web you have, the soils moisture level, and how available the Nitrogen is, and the N in blood meal is very available. Sprinkling a very little, just enough to make the area smell, blood meal over your mulches may mean something less than you spread around would be available to the plants, bacteria in that mulch would use it to digest the mulch, but that too depends on how much moisture is put down after application since a little too much could wash that blood meal into the soil.
A little too much Nitrogen in the soil, available to the plants,would cause lush, green growth that is much more attractive to many insect pests. Probably a much better way to keep the rabits put of the planting beds is to put good, tight fences in place. While the initial expense is higher than some blood meal over time those fences are much less expensive long term, and more effective.

I'm not sure there is a fence built that'll keep out a squirrel or chipmunk (the animals in question here). Maybe an electrified one. Ohhh, now there's an idea! Zap those little buggers!

I can't see me putting a fence around my perennial beds. Which is where I keep the cherry tomato. It looks good, trust me :)

Thanks for the info, though. I will just try to keep the blood meal to a minimum and not when rain is forecast.

In your situation, I wouldn't worry about how much is too much. To deter critters, you want to keep a light dusting on the garden all the time. Reapply after rain of course. Other things like heavy dew might affect it also. You will have to learn by experience how often to reapply to maintain the scent animals find offensive. You would never put a lot on at one time knowing that it has short term effectiveness on varmints. Small amounts sprinkled on very often should not have much effect on garden plants. I'd also keep it sealed in an airtight bag just on the chance it might lose some of the smell over time. Hope it works for you.

I hesitate to mention this because some folks may be put off but I've found a great predator urine that is free and very effective: human. You can just collect it in a jar and then sprinkle it around the borders of your beds. It's help keep away most pests: rabbits, squirrels, etc. I even ran a ground hog off by pouring it into his/her hole for several days. Cheap and works for me.

On the same line as the above poster, fox urine used in a small amount may be of benefit. Some predator urines can be purchased at most sporting goods stores...

Blutranes

Predator urine may help, provided those predators are native to the area and the squirrels and chipmonks recognoze that urine as being from a predator. If these wee buggers do not know that that urine is from a predator they will pay not more attention to it than they do dog urine. Around here foxes and coyoytes are not, and have not been, native for many generations so the urine from either one would have no affect on the target critters.

Now there's a fine way to make a living: Collecting fox pee. No wonder it's expensive.
I'm not sure if human pee would keep the squirrels out. They thumb their noses at me on a regular basis, why would the smell of humans bother them?

Well, the bloodmeal works, so I'll use a pinch of that around new plantings (the sort they like to dig up the best) and on patches of fresh mulch.

If you lay it on mulch you should have no problem. The blood meal will help the mulch decompose more quickly, turning the mulch into compost over time.