i have a z5u and would like to buy a tapeless unit for it

what options are available to me

my first option is the MRC1K but dont have much info and experience with it

a couple questions

what is the biggest card i can use with this unit
what brand of card is safest to use with this unit
are there any other units i should look at
i only have nf970 batteries can i use this battery with the z5u and the MRC1K attached - i heard it is not possible