Well, one the BEST things about the F75 (for me) is that you have tones in all metal mode when and if you decide to use all metal .... I use it 99% of the time.
The reason I use all metal mode is because I can actually hear the ground changing from bad to worse better than I can in disc mode .. but that depends entirely on the ground/site I'm hunting.
The best piece of advice I would give for a coin shooter using the F75 is to BUY the small coil and use it in concentrated target areas ... very good in hot dirt too because the detector is sampling less ground and gives more accurate ID's at greater depths.
You won't believe how good the small coil is until you try it for yourself.
You have to learn how to tame the beast somewhat, again site dependent, to many folks have gave up on the F75 because it's so sensitive to small objects that most other detectors simply don't hear.
Take my word for it, if it hits on something very deep and faint sounding ... 9 out of 10 times something is there ... even in bad dirt.
Granted it could be #10 shotgun pellets at 8" but the F75 will even hit on very fine rust scale pretty deep too, it's that sensitive... so it's a must that you spend the time to know the difference.
That's WHY I like the F75 so much as a relic machine, when I run into iron in a huge open field, it tells me that people were there and I slow down and investigate the site for the good stuff.
Hint ... if you are running in disc mode and even get peep of a good tone mixed in with the iron sounds ... at great depth ... dig it up

And don't be afraid to run the sens down for stability either ... it still goes deep.
I like to run mine a bump or two just below
total instability ... but I know it's language and that's IMPORTANT.
Good Hunting
Mike