Apple keyboard users may have difficulty in creating and allocating multiple keystrokes into a single keyboard shortcut in Options+ onto a button on an MX3 mouse.
or example in Excel for Mac the 3 keystrokes needed to jump to the first top left cell in a worksheet are < Fn+Ctrl+Left Arrow> - that works on an Apple keyboard, but is hard to remember and ideally should just be allocated to a single button in the Excel menu in Options+ using an MX mouse.
The problem is that Options+ has difficulty recognising multiple keystrokes in its keyboard options input field - you have to try and hit the 3 keys exactly simultaneously and that is really hard - you might fluke hitting 3 at exactly the same time, but mostly you won't achieve it.
The solution I found was simple and reliable - just plug a basic standard corded IBM / Windows keyboard into a USB port on your mac (if you have a wireless keyboard already paired leave it connected - just leave it alone while using the Windows keyboard).
Your mac may then ask you to identify keys on either side of your Shift keys - do that and it should just recognise an ANSI / US style standard keyboard.
Once the wired IBM keyboard is connected, use keys not found on an Apple keyboard to enter helpful shortcuts on your MX mouse - for example the Fn+Ctrl+Left Arrow combo I use a lot in Excel for Mac just becomes Ctrl+Home on the IBM keyboard and easy for the Options+ keyboard shortcut to recognise - 2 keystrokes together instead of 3.
Also - you may like me find the "keys missing on an Apple keyboard" like PageUp PageDown Backspace Home and End keys really useful to allocate to buttons for specific buttons for different applications in the Options+ shortcuts on an MX mouse - just use those keys from the IBM corded keyboard to create the keyboard shortcut in Options+.
When you have got all the shortcuts done in Options, make sure you do a manual backup of those settings (you only want to have to create those once!) from the Settings / Backup all devices now in the Options+ app
Logitech could have made this clearer for Apple users I think.
Also, it is really useful to have a simple USB corded ANSI / IBM keyboard (and a simple USB corded mouse) around for when the cordless Apple keyboard or mouse is not working or disconnected for some reason. Sometimes old basic gear lying around is really useful!
Hope this solution helps some out there.