Okay, here is my current setup. I found a nice refsheet for the X52
here, I hope I didn't forget anything. I have noticed a few redundant functions. Some are intentional, some not. For completeness I'll try to explain the logic behind my bindings (beware, wall of text - feel free to skip).
The Wheel on the stick obviously switches the mode. Mode 1 (red) = combat, mode 2 (pink) = flight, mode 3 (blue) = SRV. My default mode is pink, and I try to remember to reset the stick to flight mode before exiting the game.
I have the clutch function for the "i"-button disabled. The clutch button is my shift button, so each of the three stick modes has a normal and a shift mode. The shift mode is marked with a "+" in the MFD and the profile app.
The stick executes a macro on mode change. When switching from flight to combat it switches the cockpit mode to combat and deploys the hardpoints, and executes the hotkey to switch my EDHM preset to red colors. When switching back to flight it switches back to analysis mode and retracts the hardpoints. No macro is executed upon going to SRV mode. I have to say I didn't tweak the SRV mode as much as I hate the SRV and avoid it.
I navigate the UI with POV1, the first trigger is my "enter", Fire C is my back button. I switch UI panels with left and right on the POV3 of the throttle. While pressing the UI focus (the mouse button on the throttle) POV1 up/down/left/right switches the UI panels. I have disabled the "look at" feature of the panels.
POV1 also controls the PIPs in all modes. Shift mode is throttle percentages in flight mode and target selection in combat mode.
POV2 controls lights, night vision, cargo scoop and landing gear in flight mode. In combat mode those functions get shifted (apart from landing gear, which is not needed in combat) and the POV is fire group and subsystem selection.
The third POV on the throttle always controls vertical and lateral thrusters. In flight mode I use the throttle for, well, throttle. In combat I found that too cumbersome, so when switching to combat I set the throttle to 0 and use the lower rotary with my thumb for throttle / thrusters. I can be much mor dynamic that way. I have the boost on the pinkie button.
Fire B always selects the target I am looking at (target ahead). In combat mode, its shift function is highest threat, in flight mode it is cockpit mode. Fire C is my secondary fire with heatsinks on the shift function.
The toggles on the base are FSD, Camera and Map controls. In combat mode I move those to the shift function and use them for basic wing commands.
In flight mode the FSD controls are also bound as shift function of the throttle wheel. Sometimes I find it more comfortable to not take the hand of the stick to switch the FSD - or can't take the hand off. Non-shifted the scroll wheel scrolls through the targets around me. I consciously disabled this in combat mode as it is easily mistriggered and can break my target lock.
The only thing I use a mouse for is moving the reticle in the FSS.
I think that's all. This setup has evolved over time the way I found the controls logical or comfortable. I guess it's kind of hard to adjust to someone else's mindset. Oh, and I had to rename the .pr0 and .binds to .txt to upload them. I can't upload the pdf refcard as it is too large, so I have attached it as a png. Sorry.
Good luck

.