Well, back in 2006 (that's 19 years ago!) Johnm asked if anyone had found an earlier example of the floating verse "Going to Louisiana to get me a mojo hand..." than Texas Alexander's example in "Tell Me Woman Blues" from 1928.
I've been digging through that little question since the 1990s, and back in 2018 i published this bit of research, which may or may not be definitive, but it's all i got:
Going to the Louisiana bottom to get me a hoodoo hand
Gotta stop these women from taking my man
(Louisiana Hoo Doo Blues, Ma Rainey, 1925)
I’m going to Louisiana, to get myself a mojo hand
’Cause these backbiting women are trying to take my man
(Mojo Hand Blues, Ida Cox, 1927)
I’m going to Louisiana to get me a hoodoo hand
Gonna stop you women from messing with my man
(Superstitious Blues, Hattie Burleson, 1928)
I’m going to Louisiana, get me a mojo hand
Just to see when my woman got another man
(Tell Me Woman Blues, Texas Alexander, 1928)
So Ma Rainey wins the race for the hand/man line in 1925, but Ida Cox wins in 1927 if you insist on "MOJO hand/man" rather than including "HOODOO hand/man"
Cheers to all.