SI2305,
The soil is pretty compacted, but breaks apart easily. It is very much like what they consider bank run around here. Basically a reddish brown loam (I think that is the right term) with a bunch of pea gravel. Main difference it seems like it is more than 50% gravel. When I was trying to get soil samples with a trowel, 4" down, I basically had to fill a coffee can and then sift out the rocks to get a good sample of dirt. And wore blisters digging it up. Great stuff to try and grow grass in....(not!) I don't hit hard packed clay until about 16+" down. I would imagine the RB on that would be less capable, but for me, only thing hitting that is the hoe. I have a Wood's RB60, think it's about 230#. My biggest challenge has always been keeping it from biting too deep.
I did like using the FEL to dig/scrape. Took some practice, but got pretty good at it, even on the slopes. But, again, not sure how it would fare in hard clay. Definitely think you need tiller/power rake or BB/subsoiler to break that stuff up.
I also struggle with the wooded /shady areas - Oak, Beech and Black Walnut. The Oaks seem to cause the soil to become more acidic. PH is much lower (5.5-6.0) there than in my cleared front yard (which holds well at 7.0 with very infrequent lime application). Holly Trees grow like weeds at the base of the oaks. Even when the grass takes in the gravel and shade, it struggles. I am going to attack the PH issue hard now and see if it improves - if not, will look for other ground cover.....