If that the self shielding flux core wire then that's one reason why your weld is kinda rough, I mostly use .030, 70s solid wire with shielding gas.
Looked at the DR blue print, like how the head boards comes out. A 200lb trailer is nothing for a full size ATV and if some day you make another trailer, make a tandem axle trailer like the one DR sells, they can weigh twice as much, but will pull 4-times easier, because the front wheel will lift up over a bump instead of one wheel lifting the whole load weight going over a stump bump or rock, Ok back to work your on a budget, have to keep the cost under the $800.00 DR version.
Looked at the DR blue print, like how the head boards comes out. A 200lb trailer is nothing for a full size ATV and if some day you make another trailer, make a tandem axle trailer like the one DR sells, they can weigh twice as much, but will pull 4-times easier, because the front wheel will lift up over a bump instead of one wheel lifting the whole load weight going over a stump bump or rock, Ok back to work your on a budget, have to keep the cost under the $800.00 DR version.