Saving pre-order and collection reward packs?

[mgftp]

Hey guys, I have 6 packs waiting to be opened in HUT for pre-ordering, it says I will get 2 packs per week for 6 months. If I let them just collect there, can I then open them during a good TOTW week and have a chance of getting TOTW cards in them or are them limited to the base cards? Was also wondering if the same could be done for collection reward packs, I haven't completed a collection yet so I am not aware if they must be opened immediately or can they be stored for when better cards are in circulation?

Thanks, I hope I explained this well enough. I am sure I am not the only one to think it's a waste to open these packs when none of the good cards are out yet.