I am new to this as well. I had a friend give me a saddle that had a broken tree. It had fairly good leather on it so I decided to try to replace the tree and use it to ride colts. I tweaked my back a couple of weeks ago while trying to train a knuckle headed bird dog and the chiropractor told me not to do anything strenuous so I decided it was time to fix the saddle. It looked pretty straight foreward; I would just find a tree that measures out the same and put the leather back on it. Well, I could have sent the old tree out and had a new one made, but in my infinite wisdom I bought a tree from a local saddle maker that measured out right and looked about right, but as you might guess not many of the old parts parts fit right. After spending about 3 hours building a draw down stand to hold the tree still while I worked on it; I got the new horn cover fitted and on with very little trouble. The swells, which I decided to lace, were a little more challenging. I finally did get it covered after much cussing, spitting, and pulling; and I am very pleased with the fit, but the s shape of my laced seams may drive me nuts. I guess my colt doesn't know how they are supposed to look so I guess it will work, but for anyone that knows more than me, is there a secret to getting these straight or is it just a matter of talent? I did put the old skirts back on with no problems. The cantle on the new tree is shaped a little different, so I replaced the old padded seat cover and bound the new cantle back to the seat at the top of the cantle instead of putting a Cheyene roll back on it. The seat side of my stitches look good, but the back side looks like a drunk man did it. Again, is there a secret to this, or we back to my lack of talent causing the problem? As it turns out this little project is harder on my back than I had estimated. I know that none of this answers your questions, but I thought it might help you to know that there are others out here whose projects don't turn out exactly as planned. Your colt probably doesn't know the difference either.