I'd prefer handling 31% HCl over 40% HCHO. Also it's easier and cheaper to find hexamine and hydrochloric acid than to find formaldehyde and to *make* NH4Cl as in the post.
Yes, if you can only acquire OTC chems then perhaps you can't get formaldehyde so hexamine is the only way to go. If you can acquire simple but non OTC chems then paraformaldehyde and (store bought) ammonium chloride is the way to go. "Stinkiness" doesn't seem to factor anywhere into the decision.
Plus there's more "NH4Cl equiv" (ie as HCl/hexamine) used in the hexamine reaction,
IIRC, the ratio of ammonia to formaldehyde in hexamine is exactly the same as is called for in the Org. Syn. and Vogel preparations of methylamine.
and according to K.C. Nicolau it's a good thing "to suppress the dimethylamine formation".
I haven't a clue as to who K.C. Nicolau is but Vogel says the same thing so it must be true.
Perhaps K.C. Nicolau (an old school bee, if you recall him) got that wrong?
Whenever possible I prefer to get my information from closer to the source - Vogel, Org. Syn. etc.
Baseline Does Not Exist.