If you had both of the edits in one xml it probably wouldn't work in A17. The smokeleaf thingdef is in a root def <Smokeleaf> while the new recipe def should be inside a root def <RecipeDefs>.
If you want help with the XPath stuff just ask. I just finished converting some of my personal mods to use xpath patches. Here is a link that was helpful for me to learn the patch operations.
https://gist.github.com/MatchSG/13c82aae25262bcb70554fbec16973d7
You'll probably need to use the <Operation Class="PatchOperationRemove"> to delete the <recipeMaker> node.
If you want help with the XPath stuff just ask. I just finished converting some of my personal mods to use xpath patches. Here is a link that was helpful for me to learn the patch operations.
https://gist.github.com/MatchSG/13c82aae25262bcb70554fbec16973d7
You'll probably need to use the <Operation Class="PatchOperationRemove"> to delete the <recipeMaker> node.