Query specifically about Disneyland Paris…
All things being equal, would it be better to go for 4 days (3 nights) Tuesday to Friday or 5 days (4 nights) Friday to Tuesday?
This would be early July.
Family of 4 with teens.
No intention of paying for queue jumpers.
TIA
She won’t be awake for a while but I would tag @Wahoohokie 
This is such a cute name for it. 
Sounds like a sweater for Professor Quirell. 
All 3 regions of France finish on 3rd July for the school holidays. Not sure that the weekends would be any more crowded.
That said we did 3 nights, arriving around 3pm and leaving the resort around 4:30pm. This was during the Scottish October holidays, a week before England’s.
We paid for Big Thunder which we would happily do again, although you could ride it during early entry.
We did pay for the guaranteed seating for Mickey & the Magician. Arrived 25 minutes early and the stand-by line was pretty long (outside the switch back area).
I’d happily do an extra night if I could. And with the extension open by then it would give you 2 nights for each evening show.
I would generally choose more park days over less, weekend or not. Both times we went were in March, the first time mid month with no holidays, and there was a big difference in crowds between Thursday/Friday and Saturday (much more crowded, longer lines on Saturday). We only bought maybe 1 or 2 skip the line passes that trip though as Thurs/Fri were low crowds. Our second trip was later in March and close to Easter so it was just as busy on the weekdays as the weekend. We did buy one day premier access or whatever it’s called and it was definitely needed for us. I have no idea about summer crowd patterns though.
Another vote for more park days.
I regularly checked both Thrill Data and “Queue Times” before our trip and I couldn’t see any particular pattern of weekdays v weekdays. We started our trip on Sunday before Christmas and the evening felt positively deserted!
I also think that more park days will help you avoid spending money of LLs - especially if you are onsite. You can get a lot done in that one hour of extra park time, and knock out headliners at rope drop. Some you can likely reride with short wait times at night.
I would only choose shorter if I was then planning on spending the saving on queue jumpers.Otherwise more park time. Lat time we went was Halloween and it was insanely busy. Disneyland Park was closed by early afternoon for capacity. Still had a great time though. Early entry if you’re on-site is great. Crush is minimum 90 minutes due to its woeful capacity but get it at opening and then ToT in 20 minutes!