Digital BW, The Print

Hi all
Still working with EB6 and Epson 1430, my experiences with papers and drivers are getting better and better but...
Here's a few questions :

1-Someone saw a difference if you print at 360, 300, 288 or 240? (On matte paper)

2-Someone saw a difference printing a 16 bit file vs a 8 bit one?

3- Is it normal that with a loupe, the blacks show tiny white speckles (maybe due to the surface of the paper?)?

I'm reading and printing like crazy but I think I made a wrong choice with EB6. Since it's for matte paper only, the Dmax is lower than, let's say, luster paper, and what I expected. I'm aware that lot of people are searching for permanence, but I would trade a couple of years for a better output. I'm searching to match the output I had in a darkroom.

Thanks