I have a 12" bucket on my 260 BH, and can only give you the benefit of a couple of hours digging a stump growing through an old low field stone wall. My BH had no trouble going through the stones up to about 8 - 10" diameter. For the few stones larger than my bucket, I had to take a few tries to balance them to get them out of the hole (I don't have a thumb yet). I generally have a clay based soil loaded with various sized stones, but I haven't dug in my heavy clay yet. I don't think I'll have any problem, just have to get a tooth around any stones I find.
Depending on how packed your soil is, how many rocks and stones, will determine how well the 16" bucket will work. I considered the larger bucket when I bought my BH, but went for the 12" because I am planning on pulling a bunch of stumps on my property. I figured I'd be able to get a little bit deeper through the tangled roots with the smaller bucket. The 8" may have been better for that, but then too small for general digging. I had trouble ripping through roots larger than 3", but I don't think that would be a function of bucket size. Even by getting 1 tooth under the root, I still couldn't rip through. There's probably going to be a ripper tooth in my future for stump work.
As for power from the 1026R, I dig by curling the bucket most of the time. Partly because I was digging in a lot of stones, and digging by pulling on the dipper wasn't as efficient at the bucket would just "float" over the stones. Another reason is you have the most digging power by curling the bucket, and also, I wanted to dig down, and not trench. Roots were my problem, not the stones. The best way I found to dig was to loosen by curling and then pulling to fill the bucket.
Sorry I can't give you any info on the 16", but if your soil is reasonably loose, you shouldn't have any problem with the larger bucket.
Depending on how packed your soil is, how many rocks and stones, will determine how well the 16" bucket will work. I considered the larger bucket when I bought my BH, but went for the 12" because I am planning on pulling a bunch of stumps on my property. I figured I'd be able to get a little bit deeper through the tangled roots with the smaller bucket. The 8" may have been better for that, but then too small for general digging. I had trouble ripping through roots larger than 3", but I don't think that would be a function of bucket size. Even by getting 1 tooth under the root, I still couldn't rip through. There's probably going to be a ripper tooth in my future for stump work.
As for power from the 1026R, I dig by curling the bucket most of the time. Partly because I was digging in a lot of stones, and digging by pulling on the dipper wasn't as efficient at the bucket would just "float" over the stones. Another reason is you have the most digging power by curling the bucket, and also, I wanted to dig down, and not trench. Roots were my problem, not the stones. The best way I found to dig was to loosen by curling and then pulling to fill the bucket.
Sorry I can't give you any info on the 16", but if your soil is reasonably loose, you shouldn't have any problem with the larger bucket.
