A tag trailer is nicer if you are going to have a dump truck in your future either it be a 2 ton to tandem. You will never beable to haul a pintle hitch tag behind your 1 ton unless you want to make a custom front bumper you can add weight to to keep your front wheels on the ground
Even a tandem axle dump will see saw on the trunnion on the suspension if you get enough tounge weight.
If there is some way they can make the front of the trailer adaptable in the future say the goosneck part bolts on so when you do want to convert the trailer to a pintle its doable. You are most definatly going to need a gooseneck to haul the excavator with the P/U to get the hitch weight over the rear axle.
If you upgrade to a larger truck say a 5500 Chev and you use a box with fold down sides you still have the corner posts on the box to get in your way. Also if you run a longer box like a 12' dump you won't have enough reach on your gooseneck to get over the center line of the axle.
Like I meantion if there is a easy way of modifying the front of the trailer so it can be converted to a pintle pull would be good.