Sasuke's only hope to defeat CT is if he destroys it at once but that is not possible because the damage scale of his techniques won't destroy CT at once, he has to switch between both techniques you listed as you said, this takes too long, he will be sucked in before dealing considerable amount of damage to CT,We never seen anything else fired into the CTB or the CT so we don't know how strong it really is and how durable it is with standing an onslaught of attacks...
killer Bee's tbb > sasuke's arrow
and killer Bee's tbb alone was not enough to completely destroy it
again i repeat, it took Tbb, rasenshiruken, and magatama to destroy CT in it's building proccess,
all those attacks combined > sasuke switching between both techniques or using them individually, he will be sucked in before he destroys CT