2010 Sierra Scotty HiLander

You have a 4klb trailer that will pull like a 6-7klb flatbed. 
Find something good for 6-7k if you want decent power in all conditions. 
Uour intended use, distance, time of year, climate, grades and altitude will have as much bearing as the trailer specs. 
IE it would tow ok behind a midsize suv with 4k capacity in Nebraska on a cool spring morning. It would be almost prohibitively bad at 10kft uphill in the dead of summer. 
Since you don’t have any towing experience I’d say don’t err on the side of barely big enough.