MEV: just checking that I've got the rules right!

Hello everyone! I have a MEV valid from 22 June to 19 Dec 2024 (90 days). I had originally only applied for a single entry visa to visit Paris for 8 days in June, so the 6-month MEV was a good surprise!

My plans for my original trip haven't changed at all, but now I'm hoping to make the most of this visa and plan a couple of other short trips. I understand that I can spend 90 days total in the schengen area but what are the rules for how these can be spaced?

My current thoughts are: - my original trip to Paris in June for 8 days as planned - a short trip 4-5 days to either Italy or Spain in July - a weekend trip somewhere tbc in Aug - a short trip in Dec to Berlin to experience Christmas in the city for a week tops

I definitely won't be exceeding my 90 days, but will be short spacing of trips between June and Aug be problematic? I plan to have confirmed return tickets and accommodation booked for all of these. It's just that I work as a University lecturer, so my holidays have to be planned around the summer term!

Any help would be greatly appreciated - thank you!!