I have made spread sheets previous for parties. I went back to old fashion paper lists. A note book with one page per day. Including menu plan and shopping lists. I think your dinner parties are perhaps more elaborate and maybe more formal than mine. Planning principles are the same.
Putting a time beside some items is both useful and a reminder that your efforts match where you should be on the countdown to when guests should be expected and the party is to begin.
I start with things that can/ should be done xxx days in advance, move forward to the day before, which for me should be most of it, and day of for actual prep cooking that is needed. I Plan to have everything that can be done ahead before guests arrive. There is no reason to be polishing glassware and you haven't had time to change into your own party pants yet.
I also keep a running list of house keeping / cleaning with a final touch up the day of. ( This list could be used again.) (( well, maybe some adjustments as needed)).
The two caveats I have, once I get ready to set the table, the 2 cats are sent upstairs to play. They like to help, and I don't care for them jumping on the table. 2ndly, any fresh flowers are only brought out after they are gone. They are allowed back downstairs once the party starts, or else there would too much yowling. Surprisingly, they aren't interested with more people around and they go elsewhere and settle down by themselves.
I choose menus based on what can be made a day ahead/night before and day of. There is very little if any, that I do during dinner. Just before dinner, I usually ask for helper(s), dress the salad, slice bread, nothing to much but and extra hands are useful and they're hanging around anyway. I am not fussy about having people in the kitchen while doing last minute prep. I am fussy about what tasks I assign, and to who is capable. The least is made to feel equally valuable filling water glasses.
I don't entertain often enough, and I tend to twitch before hand. But really, I am pretty comfortable once I actually start working on the plan of attack. I think making a complete check off list is both soothing in this aspect as well as handy. One other thing I do, is bring out all the serving dishes a day in advance, and a serving fork/ spoon for each with my list in hand. Then set them aside until time to use. There is no reason to say, oh I forgot the xx.