Personally I don't think there are any wrong or right settings for the Deus, all depends on where you live, local mineralisation, and the type of sites you detect that dictate the settings.
I always leave the tx power on 2 and adjust the sensitivity to its highest stable setting, usually left on 90-95. Running a high tx power will also drain the batteries at a much faster rate.
As for my settings, pretty much the same as Ramjet, based on the well known Hot Program (modded Deus Fast) .
Frequency - 17.3 kHz for most areas as my pre-decs are reasonably shallow.
11.7 kHz for coinage in deeper soil profiles, or if I want to enhance the response on the high conductors, especially deeper threepences or coins that are possibly on edge.
The frequencies below 11.7 can be pretty noisy in some locations if near emi sources, requiring a drop in sensitivity to maintain some sort of stability. I honestly haven't given much time to the 4 & 8 kHz frequencies, as the upper two have been doing a pretty good job so far.
Tones - Fulltones
Reactivity - mainly 3, though will use 2 in open ground with minimal iron/junk
Silencer - turned off
Audio Response - 4
Discrimination - just enough to discrim out rusty iron nails, which is close to the hot program setting of 5
Ground Balance - this is probably one of the more important settings to get right on the Deus. If the ground balance is not correct, none of the other settings on the Deus will make a difference with regards to improving depth.
I prefer to run with manual ground balance vs tracking for 90% of my detecting. The mineralisation in my area is reasonably low and uniform, so not much needs to be done once the GB is manually set for the area, other than the odd adjustment on the fly. I usually run a couple of points lower than the suggested figure for a little more depth, so long as stability is maintained. If you get touch sensitivity on grass and objects, the GB is set too low.
I avoid using tracking, as it underperforms on any locations with iron/junk. It will calculate a mean ground value based on the junk if it cannot consistantly read the ground, which greatly reduces depth and hinders the unmasking ability of the detector. Sticking with the suggested factory GB preset of 90 is not suitable either for most of our soils, if exclusively used it may compromise depth and result in missed targets.
As an example of what tracking will do in junky ground, I tested tracking in my backyard which is full of rusty nails and non-ferrous junk. The tracking consistantly calculated the mean GB value at around 80-85, most likely due to reading on other targets in the ground vs the actual ground itself. I planted a $1 coin at 6" using reactivity 3, and the Deus would not signal at all on the coin.
Dropping back to manual GB, I managed to average a true ground value of around 70 on a clean patch ground, and upon adjusting the manual GB back to 70 and below, the coin was then clearly heard.
So if using tracking and you suspect you aren't achieving good depth from the Deus, switch over to manual GB and give it a go.