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I can give a little help but you might want to study part 15 a bit more, especially 15.209 and 15.219. Be aware that general restrictions may appear in other sections.
Section 15.215 Additional provisions to the general radiated emission limitations.
(a) The regulations in §§ 15.217-15.257 provide alternatives to the general radiated emission
limits for intentional radiators operating in specified frequency bands. Unless otherwise stated, there are
no restrictions as to the types of operation permitted under these sections.
Since the 100 mW, 3m restrictions are in 15.219 check that. It appears there are no restrictions except for damped waves which is covered in another part 15 section.
So, it appears CW is OK.
It has been so long since I researched this that I no longer have my bookmarks (and memory of the details) but I recall finding sites which discuss what you propose. Try a search on MW, MW clubs, MW DX, and similar medium wave topics. You’ll probably find lots of information.