How much it would be harder that does not make any sences to me as I know that I have to make it. So I have to make it with minimum configurations (default).
I have to make a wooden box, the box has to hold some equipment.
How big should I make the box? I dont know the size of the equipment, so I have to make the box with the minimum default size.
I suggest you first describe the amplifier you're trying to build - presumably it's a valve one?, so why not just buy a choke when you buy the mains and output transformers.
Although that is an acceptable way to describe inductance it is much more common to describe it in actual Henries. Thus, you need a 1H inductor.
That's quite a large inductance really. Are you sure you need it that large?