The key difference here is that "All the way up". The first part of the sentence (the "even if") has to show that you are trying something to the limit. If you "leave now" you can't leave any earlier. If you blow the balloon "all the way up", it can't bet any bigger.
In your example, the person blowing up the balloon might not have wanted to blow it "all the way up", in which case, it would make sense that won't get very big, and so what the speaker says sounds redundant or off-point.
So when I said "it would make sense that it won't get very big", that "would" was referring to the potential result of the person blowing up the balloon only a little bit, not the fact that the balloon won't (will not) get big, if you decide to try and blow it up.
As for the "even if ... will" construction, "will" is fine, although using "would" also sounds okay.
"Even if we leave now we still wouldn't make it on time" still sounds okay to me. The difference is that you might use "will" if you are a little bit angrier or more urgent. It just slightly changes the tone of the sentence.
The Language Level symbol shows a user's proficiency in the languages they're interested in. Setting your Language Level helps other users provide you with answers that aren't too complex or too simple.
Has difficulty understanding even short answers in this language.
Can ask simple questions and can understand simple answers.
Can ask all types of general questions and can understand longer answers.
Can understand long, complex answers.
This answer was given within 60 minutes of the question being posted.
What are "disagrees"?
When you "disagree" with an answer
The owner of it will not be notified.
Only the user who asked this question will see who disagreed with this answer.