You will need to experiment with the photo paper, many people here will give you many opinions
on what they use. Plain paper, magazine paper, pnp blue, sticker backing sheets, transparency sheets etc etc etc.
Just play with you temperature, and pressure and you'll find something that works.
pnp and thin papers take less pressure. Thick papers take a littl more pressure, not much though.
The etchant isn't as critical just follow the directions for each. They will all etch fine, just take different times
but you can see the progress so it's not big deal.