WHATS THE BEST AMMO TO USE FOR MY 32-20 1908 MODEL YEAR

Any current production major brand. Don't worry about "rifle ammunition" warnings, .32-20 is and always has been a rifle cartridge and is often so marked.

You really have no choice today. Any currently-made .32-20 ammunition you find will be loaded with lead bullets at pressures suitable for use in any .32-20 revolver. The old .32-20 high velocity loads were sold for use only in more modern rifles in that caliber, such as the Winchester 1892 and several others. It has not been factory loaded since the early 1960s. Reloading is recommended if you plan to shoot your revolver much.

I've chronographed some Remington factory ammo made in the last fifteen-twenty years; only made around 1100 fps as I recall and that was from a rifle. For a handgun, I'd subtract about 250-300 fps. Indeed a mild load, surely safe for anything in decent condition.