the full knowledge goes both way,
if minato sees obito throwing the orbs to form the barrier, then he himself throws kunais further away
or he uses chakra arms [
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] to carry kunais underground [
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], outside the barrier
the bombs take time to charge up to their full size so time isnt an issue here
I would say that he should be allowed to use kunais that are already lying at some place like the open ocean [
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] to redirect them since he has used them in the manga against the kyuubi and the juubi
for redirecting the juubi dama, there are two options
either use space-time barriers, (he can use clones for help)
or use chakra arms to touch the bombs and then send them away while he himself remains inside the barrier