The through-hole versions of the 1N4001 to 1N4007 are all the same size.
They are all rated for 1Amp continuous.
Only the reverse voltage is different.
I suggest you buy the 1N4004 instead of the 1N4001.
The xxx5 to xxx7 should only be used for high voltage (mains), since they have a slightly higher forward voltage.
That is however not a big issue in 'most' applications.
The bigger (3Amp) version of the 1N4xxx starts with a '54'.
e.g. 1N5404.
Leo..