I have developed my first negatives this week. I processed them one by one in trays.

Ilford FP4 PLUS, 4x5'', in Xtol, for 7:15 minutes with constant agitation (lifting the tray gently, and putting it down again, on three different sides).

Looking at the negatives, they appear to be evenly developed, and extremely sharp under a loupe, so I am happy with that.

* But how do I know if a negative has been properly exposed? Will I have to print it to know for sure?

I don't have a negative scanner, and I couldn't use the LF enlarger yet, so I was only able to do some contact prints onto some old Ilfospeed RC IS 3.1M that was there.

The prints didn't turn out to be very nice, there was a lot of dust on that glass used to press the negative onto the paper (maybe 3-4mm thick), and they are also not very sharp.

* Is it possible to (approximately) calculate height/aperture/exposure for contact prints/enlargements, or do I have to make test strips for every negative?

* What settings should I use to make sharp(er) contact prints? Large/small aperture, low/high height of the light source? Is it OK to use that glass plate or is there a better way?

Thank you for your help!