the front tires calls for 26 psi and with a heavy load like the boulder they are somewhat flat. The R4 tires are likely better at that but wanted the ag tires for the better traction and mud shedding capability
not including hoses and support angle welded to bucket. Did my own labor and welding using the old miller diesel welding machine with 6011 rods. The mounting needs to be sturdy to take the force of the 2 inch cylinder closing force without flexing the point where mounted to bucket. The base of the Grapple is a 1 inch plate that I welded to a 4 by 4 by 3/8 inch thick angle and then welded to the top of the bucket with full penetration welds all around. Looks like it worked because after moving about 20 or so large rocks yesterday there was no problems at all. Moving these rocks without the grapple would have been a time consuming process with chains and pushing since it is very difficult to get the rocks into the bucket cleanly to where it can be lifted without falling out
Yeah you can find it on ebay. Greens Machine Shop has an ebay store. I can't remember off hand their dedicated website though.
I'll tell you what. The more pics of see of that thing the better it looks. I had abandoned the idea of looking into a weld-on grapple and was thinking more along the lines of a stand-alone grapple. But that looks very nice. Good professional job on the welding.