coiltek 6" round mono

Hi Members!
Went out for a swing today around some old diggings today in central qld with my son. We found all sorts of steel targets so tiny we could hardly pick them up out of our hands. They were mainly small bits if wire about 2mm long. I use a 4000 and had on a 10x5 coiltek mono. A friend has a 5000 and found 7 bits last week. Then i started doubting my machine and settings!
Do machines have to be serviced regularly?
Also, Has anyone used the 6" coiltek round Goldstalker mono? What settings would you use with a coil this size?
Any help would be great!

hi goltzy.
I have a 6" coilteck and mainly use it for pinpointing . The factory settings work fine for this small mono. It has a slight edge on the 11 and 8 monos for the flyspeck size bits !! If the ground permits you could try cranking up your gain for a bit more sensitivity. (or try sens extra)
Stopsy is the man on the 4000 settings , give him a PM for his tips !
DB