You do realize that the 8% and 4% can be ramped up quite dramatically if needed, right? Currently, Chinese pipelines and railroads to Russia and Kazakhstan stand at 20 and 25% utilization, respectively, and more infrastructure is in the planning stages.
As for land based protection for IOR shipping, Gwadar is much closer to IOR energy lanes than any of India's ports are. Even if China can't offload any oil there, China could certainly use it as a staging point for a heavy contingent of submarines - subs, that in a time of war, could be loosed to raid Indian shipping in the IOR at will.