Genuine or non oem HP toner works for me. For the pitting problem I
transfer craft metallic foil on top of the toner before etching. It's a
well known practice and reliable.
Rather than using acetone or citronella to prepare/clean the copper I
use 220 grit sandpaper and an iso-propyl wipe which makes the toner
'grip' the oil free copper. Even fingerprints can interfere so handle
the edges of the PCB. As a test I polished/lapped copper and tried the
identical transfer with poor results all other things being the same.
Also, before I did the metal foiling, I used to use a silver sharpie to
'fill' in the toner transfer for any breaks or potential pitting and
then etch.
I have done literally hundreds of double sided boards and even boards
for RF use to 1Ghz with toner transfer. It works.
Ancel