At 1600 I use Fuji Neopan, developed in Xtol 1:1, excellent for 18*24 or 24*30, compared for its speed fine grain. A bit on the contrasty side, so grade 1 or 2 paper is recommended. Even 30*40 enlargments can be done.(posted 8863 days ago)At 6400 I used Kodak TMZ 3200 developed in Ilford DD-X or my favourite Tetenal Ultrafin Plus, adding 15% of development time. No it is not very fine grain, but works nicely for taking pictures of bodies, enlarged to 24*30.
Regards,
Wolfram