Hi.
I´m kind new on this stuff, but for my tiny experience, i would recommend an iPad mini 2 or 3 cause is enough...
If You could spend more, a mini 4 or iPad pro would be better.
I was on same position a few days ago, cause i had mini 1 and because of my budget, buy a mini 3 and i´m, at the moment, very happy with it...
Hope i could help.
M14
Donald is right 4 k is no problem its also one of the brightest tablets on the market plus i can do video editing on the go
I use pinnacle studio pro
Transfer files using the applecardreader dongle
Just make sure to buy the 256 gig version with 4k files you will need it!