How do you know where the descriptive word goes in the sentence? Is it a matter of preference?

Yes, "winces" are not things you can use to grab things. As for the second one, personally I prefer not to end a sentence with an adjective as well, but it doesn't make much difference. I'd prefer "hooted with excitement" actually.

Practically speaking, you put the descriptive word as close as you can to what it is describing. Everyone knows that a shotgun doesn't wince, but people who have been trained to edit will wince at your sentence and imagine a wincing shotgun.

As for the second, the normal way to hoot is excitedly, I think, so you should cut the adverb. If it's a marked state (ie: not normal), then I think you can put the adverb in front or behind. English teachers would tell you that they go after the main verb, but I think there are rhythm and scanning problems (even in prose) that make it better for the adverbs to go elsewhere. If you don't care, and can't say why you put it in a certain place, then you'd better move it to after the main verb. It goes in front to emphasize . . . which means different things to different editors.

Commas are a bear, and if you plan to write, you might as well take three or four weeks to check every single comma you've written and internalize the rules. For most American writers of fiction, you'll be following the Chicago Manual of Style. That means Oxford (serial) commas, and all those weird rules about when to use them and when not to use them when you are writing a series of adjectives that are alike (or not alike) in quality.

BTW, the Purdue OWL (Online Writing Lab) is a fabulous, free resource. Here's what they say about adjectives and adverbs: https://owl.english.purdue.edu/owl/resource/537/02...

The way you have written the sentence it sounds as if the shotgun winced. That is not what you mean, I'm sure, so she is just rearranging your words for the sake of clarity. There's now particular rule about where the descriptive word goes, it just has to make sense.

Trust the editor, the corrections are right. The way you put it, the shotgun was there with a wince on it. And, considering "hooted" to mean 'yelled', then "he yelled "excitedly". See the difference?

Yours could sound like she used a wince to pick it up.

She grabbed the shotgun with a glove.