Here's a link to my mini hoe build on flickr. I started out with a 14 hp kohler that's what was on the tractor when I got it. I built this back in 2011... It's got a HF engine on it now. I have a 11 gpm 2 stage pump. moves fast not under load at a lower pressure when you get a load it drops to the 2.3 gpm single stage for more power without lugging the engine. I have 2.5 x 8" cylinders. I can dig down to 6' but the highest the bucket goes is about 3'. I wish I built it with a better swing. I think I'm only at about 100deg. total 170 or even 180 would be a lot better in hind site. I may correct that when I tear it down to weld in the bushings. I think I'll ust a little bigger cylinder for the swing too. I only have 1.5 on the swing and it swings the boom just fine unless your trying to sweep dirt back into a trench. Just doesn't have enough ass for that. I built this so it could be removed in short time. The Loader and the back hoe are attached to each other and the tractor is merely a means to move them around and provide the hydraulic power. It very rarely got run much over an idle.

https://www.flickr.com/photos/jim0421/albums/72157628142173323

I know a lot about a lot of things BUT I still have a lot to learn.
Life is what you make of it. So, why not make a working machine to make it easier.