If grain is a big concern, the real answer is to move to a larger format
yes, of course but.........
If you want real big format (=50X70cm) printed from 35 mm negatives and grain is your concern,
Try the next films:
Pan F - Perceptol (Ilford)/CG512 (CG Hamburg)
Rollei R3 (iso 50) - CG512 or Rollei low speed developer
Fuji Acros 100 (iso 50) - CG512
Agfa Copex (iso 25 -40)- SPUR Nanospeed
Kodak Imagelink (iso 25)- SPUR Imagespeed
Efke 25/Maco UP25 - AM50 (Amaloco) or Tetenal Neofin Blau
Discontinued but sometimes available:
Kodak technical Pan
Agfa APX25
Best camera for these kind of films and high resolutions: Leica M serie, preferable with 1,4 or 2,0 lenses because films are about E.I. 25 till E.I. 50.
Even some films (the microfilms) can give over 300-500 ln/mm resolution, (=far over the optical resolution) you will see the differences. Some of these films are also available on 8X11mm (Minox) format.
Scanning can be a problem, best is to print via an enlarger on classical photo paper.
Just an alternative to a medium format camera.
Best regards,
Robert