how do you determine what a good weight is according to height and breed?

You know how when you go to the doctor and he has that fancy old chart that matches your height with your weight to see if you're the right weight? Is there such a thing for horses? I'd like to see if Jubilee is a good weight for her height and breed.

From what I've read, there are too many variables (height/length/breed/etc) to have accurate/useful weight charts, and the typical methods or using a weight tape or even one of the standard formulas (which takes length into account) can easily be off by 20% anyway.
I think it's probably more useful to look at one of the 'body evaluation/scoring' systems you can find on the web rather than by weight alone. I've seen them in articles from various agriculture departments and vet schools. They 'score' your horse's body condition based on a number of different factors.

I would agree with Painthorse. Take QH's for example, up here in Canada the reiner's like a small more compact horse around 14.3 hands. While the working ranches prefer the bulldog type QH which are chunkier in their build and around 15.2/15.3 hands.

Here's an example of how to determine your horse's overall BCS:
Body Condition Scoring of Horses

Thank you, both of you!!

The link is great. I'm going to take a close look at it. Thanks.

Body Condition Scoring for Your Horse

Isn't that what I just posted Peggy??? LOL or didn't you like my version....

LMAO I didn't even read the others before posting that I was in a hurry SORRY