for travelling, i recommend explorer 1 series. Do go to the shops to tryout the traveller and explorer series, u will find that the traveller series is *abit* flimsy compared to the explorer.
I am no expert but i read somewhere that we should divide the max load of the ballhead by a safety factor of 3 when we want to determine if the ball head can support our setup.
Therefore, Markins Q3 should be able to support 1DMkIII n 70-200 2.8IS. But u might need to upgrade the ballhead if you intend to do more next time. For tripod max load, I think you need to factor in the weight of the ballhead as well so u might be cutting it a bit too close if u choose a 4kg maxload tripod.
I bought a general purpose PG-50 plate. Looking to upgrade to a L plate next.