What marm said, actually the way I said it might still be restrictive for that...
Do keep in mind, that this is primarily to clarify what we think of as being a side-mounted shuttle. The most important thing about it is that the engines can't be directly under the orbiter in a way that makes balancing of weight and thrust easy as fuck. Hmm, that previous sentence is actually a good simple summary to use in the text that will be seen by everyone.
The super complicated language doesn't have to be seen at all except by maybe 5% of people, I'll chuck it in some hidden extended details section that most won't click on, because they're not going to do anything that relies on knowing it. It'll only be ever pulled out when someone tries to be clever and edge the definition in a way that breaks the spirit of it. I'm hoping that any instances of edging the complicated language just ends up with something unexpected in a cool way, if the definition captures the spirit of what we want well enough.
Aye, I'll think about it. At least it's 90% ready, right?