Orientation discrimination task

Hi all,

I have maybe the silliest questions, but here we go…
I am trying to make an orientation discrimination task using two-alternative forced choice procedure. For each trial I have two circular gratings (diameter 4° ;spatial frequency 3 cycles/degree; contrast 80%; mean luminance 44.5 cd/m 2) which are presented sequentially, each for 350 ms, interpresentation time chosen randomly from 400–600 ms.

My questions:

  • how do I set up the 4 degrees diameter?
  • how do I put the contrast at 80% and the luminance
    -most importantly- how do I make sure each trial is 350ms? I cannot find how to set up this duration.

Also how do I make sure that the difference between the grating is adjusted logarithmically using two interleaved 1up 2down staircases?

Thank you all.
PS. I am just starting my journey with PsychoPy so if this questions is not supposed to be here please be kind and just let me know .