Chat
That's not embarrassing, it's great! You get nowhere unless you're willing to experiment a little because almost nothing is perfect "out of the box" (especially when it comes to driving goats!). And Koby is lovely too by the way.
Your shafts are fine. The shafts are for stopping and turning the wagon, not pulling it, so from a mechanical standpoint, slanted shafts are not a problem. The angle on yours is not extreme. Having the back part of the shafts rounded is not a problem either, but if you used elbow joints to create right angles then you could probably shorten your traces a touch since there would be a little more room behind Koby's legs.
In a 4-wheeled vehicle the shafts should not "float" in the shaft loops. "Floating" is how you measure balance on a 2-wheeled cart. A 4-wheeled wagon supports its own weight, so the goat has to hold up the shafts (which are not heavy enough to worry about). For this reason you don't actually even need shaft wraps on a 4-wheeled wagon. Shaft wraps prevent a 2-wheeled vehicle from tipping backwards when you lean back on the seat or if you go up a hill. I believe you can remove them from the Hoegger's harness and that's exactly what I would do in this case. Just don't forget to put them back on when you put Koby to the 2-wheeled cart! In fact, you may want to buckle them through the footman loops on your 2-wheeler so you don't forget.
It doesn't matter too much where the footman loops go as long as they are far enough back that they don't interfere with the placement of your shaft loops (some footman loops are positioned so that you slide the shaft loops all the way back until they hit them); and also that they are far enough forward to be an effective anchor for your holdbacks. With a goat Koby's size, you definitely don't want to put them too far forward because your holdbacks won't reach. Also don't get them so far back that you have to take up five wraps worth of slack.
Your singletree is actually just fine in the photo. It does not need to swing freely and will be safer if it doesn't. Most only have a couple of inches of play in them--just enough to accommodate movement without allowing the singletree to ricochet wildly back and forth. So you can probably take out those loops of rope you used to lengthen the distance between the singletree and wagon. I like the height of your single tree. It should be as close to the level of your breastcollar as reasonably possible. The doubletree on my team hitch is lower than I like, but that is because it's fastened directly to the wagon tongue instead of to the front of the wagon. If I had welding skills I would attach a bracket to the front of the wagon frame that would hold the doubletree, but since I don't have those skills I think I'll just leave it on the tongue. A low tree attachment is designed for animals using a collar and hames, not breastcollars, so definitely don't attach the singletree under the shafts.
Your shafts are fine. The shafts are for stopping and turning the wagon, not pulling it, so from a mechanical standpoint, slanted shafts are not a problem. The angle on yours is not extreme. Having the back part of the shafts rounded is not a problem either, but if you used elbow joints to create right angles then you could probably shorten your traces a touch since there would be a little more room behind Koby's legs.
In a 4-wheeled vehicle the shafts should not "float" in the shaft loops. "Floating" is how you measure balance on a 2-wheeled cart. A 4-wheeled wagon supports its own weight, so the goat has to hold up the shafts (which are not heavy enough to worry about). For this reason you don't actually even need shaft wraps on a 4-wheeled wagon. Shaft wraps prevent a 2-wheeled vehicle from tipping backwards when you lean back on the seat or if you go up a hill. I believe you can remove them from the Hoegger's harness and that's exactly what I would do in this case. Just don't forget to put them back on when you put Koby to the 2-wheeled cart! In fact, you may want to buckle them through the footman loops on your 2-wheeler so you don't forget.
It doesn't matter too much where the footman loops go as long as they are far enough back that they don't interfere with the placement of your shaft loops (some footman loops are positioned so that you slide the shaft loops all the way back until they hit them); and also that they are far enough forward to be an effective anchor for your holdbacks. With a goat Koby's size, you definitely don't want to put them too far forward because your holdbacks won't reach. Also don't get them so far back that you have to take up five wraps worth of slack.
Your singletree is actually just fine in the photo. It does not need to swing freely and will be safer if it doesn't. Most only have a couple of inches of play in them--just enough to accommodate movement without allowing the singletree to ricochet wildly back and forth. So you can probably take out those loops of rope you used to lengthen the distance between the singletree and wagon. I like the height of your single tree. It should be as close to the level of your breastcollar as reasonably possible. The doubletree on my team hitch is lower than I like, but that is because it's fastened directly to the wagon tongue instead of to the front of the wagon. If I had welding skills I would attach a bracket to the front of the wagon frame that would hold the doubletree, but since I don't have those skills I think I'll just leave it on the tongue. A low tree attachment is designed for animals using a collar and hames, not breastcollars, so definitely don't attach the singletree under the shafts.