Best video format - DV, MP4, MOV...?

Hello!

I would like your advice as to the best video format for use in iMovie 10.1.1.

In 2009, before I migrated to Apple, I digitalised some 50 Hi8 family videos. Later, when I migrated to Apple, I had to convert them to a format compatible with iMovie. Then I did not have time to go any further. Now that I am retired I would like to edit the videos but I find myself with sometimes as many as 4 versions of the same file, with widely differing sizes, and I do not know which I should choose and which I should delete. For example, these are the four versions I have of one video:

Format size

TS 1,55 Go (in Finder it says that this is MPEG-2)

DV 9,55 Go

MP4 772 Mo (in Finder it says that this is MPEG-4)

MOV 5,53 Go (in Finder is says that this is QuickTime video)

Sometimes the format is MPG.

My question, therefore, is which format should I keep? If I have to choose between quality and file size, I would choose quality.

I see that iMovie recognises the DV and MP4 formats but not TS or MPG. That simplifies my choice, I think.

To my surprise I also see that iMovie does not recognise QuickTime files, even though it is an Apple software!

I have searched an answer to my question elsewhere on the Internet but I have found conflicting reports. Hence my posting on this forum.

Thank you very much for taking time to reply!