Usually one minute treatment is more than enough 

Usually one minute treatment is more than enough 

Agree, one minute is fine.  All you are doing is wetting the membrane to create a solvent interaction.  

Methanol activates the chemical groups in the PVDF membrane, allowing the membrane to interact with proteins. You will need to soak the membrane in 100% methanol for at least 30 seconds. You will not need any methanol in the transfer buffer if you are performing and western blot transfer on to a PVDF membrane. However, for nitrocellulose membranes, you will need up to 20% methanol in your transfer buffer.

remember to wash excess methanol off after the 30"-1' methanol activation. 1' in the western transfer buffer is enough to wash excess methanol off.

Ethanol works just as well if you would like to avoid the toxicity of methanol. The wetting of PVDF membranes has been covered before on Researchgate: 

https://www.researchgate.net/post/I_want_to_know_why_we_use_methanol_for_activation_of_PVDF_membrane_before_western_transfer

Cheers!