Thank you for the great work you are doing.May I know when one can use 'when' / 'if', and 'whether'/'if'. What semantics and syntactic meaning does each carry.
I think "If" has the sense that the event might take place and might not, but shows more probability that it won't.
While "when" is more objective, it does not show any probability.
I once read a poem that says:
"If you go,
when you go,
and I should want to die"
I hope that helps.