PH.....I have only owned my LTD since the 2nd week of January, so far the weather has allowed me to swing it for a total of 18 hours...so...I am by no means "experienced" yet but I'll give ya my two cents. First off I hope you ordered the machine from a dealer who is well versed in the Fisher machines, I got mine from Lil John at Finders Keepers in Edgewater, MD and his insight has been invaluable so far. I'll tell you what he told me; start with BP mode, Disc at 21, sensitivity at 50 and either 3H or 4H tones. According to John the LTD with sens at 50 is similar to the original F75 at a sens of 95. The initial settings run smooth and quiet here in PA and I have not "played" with the settings too much yet.
I have been a White's user for my entire 5 year MD career and was worried about switching to an unknown machine but I can tell you that fear vanished in the first three hours of swinging the LTD, the machine is light, well balanced and very easy to set up so I'm sure I won't ever look back. Not only that but in a local park that I was ready to give up on I have identified at least 6 good repeatable coin signals that are pinpointing at 10" plus...obviously I need to wait for the spring thaw to dig these targets but that didn't stop me from putting little rock piles and logs at these locations to make finding them again easy.
My best advice would be to read, read, read and talk to current F75 or F75 LTD owners to get comfortable about the machine before it arrives. Check out Tom Dankowski's website if you have not yet done so, this man is a wealth of knowledge and he goes a long way to prove his theories, his site is Dankowskidetectors.com and everyone in our hobby should read his articles on masking.
I have the manual for the LTD in .pdf format if you would like it send me a PM and I'll shoot it to you.
Good luck and HH
Dave