Watch Steve’s and or Hudson Henry’s excellent z8 setup video’s on youtube or if interested in even more info, buy Steve’s Z8/9 setup guide book. Good value for what it provides And fall back for settings and advice for functions you are not using yet. Only watch shooting banks, custom button assignment and i-menu customization portions to better understand my cryptic reply. Steve does not use or recommend banks, whilst Hudson does. Bank portion of hudson is very good and useful if you shoot multiple genres.
Here is slighty longer version for most important part. Banks is complex Pro version of U1, U2 etc settings of Nikons consumer line cameras. Shooting banks, saves all settings done under shoot menu to Shoot memory A-D. Custom settings banks are also confusingly named A-D and are totally seperate from shooting banks. This only stores settings under custom settings menu. Shooting and custom banks are not and cannot be linked, so if switch to B on shoot, you will still be under A under custom settings, so allows up to 16 combinations.
If all banks are set the same and your preferred defaults, it won’t matter much if switch banks inadvertent. If Shooting Bank A is setup with your preferred settings, it is easier to copy bank A to B-C than to change bank and do all setup changes multiple times (ie once for each bank). Rest is to make it harder to switch inadvertantly
Check your i-menu if says Shoot A / B on any icon. Is like that on camera defaults, so easy to click on by mistake and switch banks. Remove this from i-menu if not used and replace something that you would use frequently for easy access without menu diving.
I think fn1 or fn2 button on front is also for changing shooting bank when held in with control wheel to change on camera default settings. Assign button to something else that you would use. This is stored under custom settings bank, so also needs to be copied from Bank A to D to make all settings under the customs settings the same accross all banks.
