The Ace 350 should serve you well as a start out detector. If you do intend to do parks, the small sniper coil will almost be a necessity in areas loaded with junk in the ground, something to think about for the future.
Since you are going to try out the Ace down the beach, run in all-metal or jewellery mode, so you don't miss out on any possible jewellery. If running in wet sand, run about 3-4 bars of sensitivity to eliminate any false signals. You will also endure reduced depth as well, but that is the sacrifice you have to make for a stable running machine. Dry sand I tend to run 3/4 to full sensitivity, depending on interference from EMI, and how recent the last tide was (sand can still be wet at depth, but dry on surface). Bottom line is, just have a play around with the sensitivity whilst you detect, to find what setting is quietest for that particular area.
Dig repeatable signals, single bell tones can be $1 coins, crazy multiple bell tones are usually $2 coins or bottle caps. $2 coins will make the detector go crazy with repeatable bell tones, whereas bottle caps tend to have a signal cut at the end of the bell tones, you will see what I mean when you find some to compare. Other coins tend to have more mellow but solid signals, whereas bottle caps, foil, ring pulls and Calipo foil caps are usually quite loud, sharp and harsh, and sometimes broken up signals or popping type signals. 5c coins that fall down towards the foil range, can be picked out due to having more solid repeatable signals than the junk.
Non repeatable signals can be a number of things, falsing due to salt, loose cabling at the bottom of the detector shaft, and deep targets that won't quite register as a solid signal. I generally don't bother with these targets, otherwise I will be there all night chasing targets that may or may not be there, other people may chose to investigate further.
Check that newly acquired target with the pinpoint button, this will indicate the possible size of the target and its exact location. The DD coil acts as a blade through the sand, with the signals registering as they pass under the centre axis of the coil For example, if you get a bell tone thinking it is a coin, then check with the pinpoint button and find it is a broad and ill defined target, chances are it is a larger target like a aluminium can similar at depth. Most targets that you want to dig should have quite a small and defined pinpointed area.
Not all good signals can consist of single repeatable signals, items like rings can give off double signals on each swing of the detector due to their shape. I recently nearly missed a silver ring due to this, hence why I dig all repeatable signals.
The large DD that comes with the 350 is probably my favourite coil, especially at the beach, very easy to pinpoint with compared to the concentric coils (have the same on my 250), better depth capabilities.
The main difference between the two detectors is a slightly higher frequency on the 350, large DD coil as standard, and an expanded iron range for relic hunting, otherwise they are pretty similar, and also have similar performance capabilites.
If you ever have any questions, there are a few 250/350 owners on the forum that will be more than happy to help out, some with most likely more experience than me.
