Big multiflue 39 x 39 cap installed a few weeks back now. Got it from Chimney Cap Corp who supply most of the major retailers including HD. I was able to order from them direct due to the size of the cap as most box stores wont carry it. Transaction was smooth and quick and I think I paid $380ish.... Product is made in Long Island, NY got here in 3 days from order. Quality and customer service were great very knowledgeable (I almost ordered the wrong size and they second checked me). This also gave me the ability to grind out and fill all the cracks in my crown with hydraulic cement but eventually the crown will need to be completely redone. I also tarred all the flashing.
My buddy was only up there for the pic so the tie off rope was only for me. Also not picture was the harness I had around me and around the chimney. Stories??? haha house is built into a hill so 3 on one side 4 on the other something like that and 12 pitch roof to add to the fun..... Towards the end I was glad I was finished cause I was getting a little comfortable up there which always leads to recklessness. Four 1-3/4 tapcon screws on each side into the crown, ratings state 800-1200 lbs of force for each screw. I may have overdone it but my crown isnt in the best shape. If you blow up the first pic you can see the screws.
Forgot to mention this.... the top of the cap has 8 3/8 nuts so you can remove the big piece of sheet metal and get nice sweep/inspection access to all three flues. I will get some pics during my half season inspection.
I've been toying with getting one for mine too, I have three flues so it may be a bit bigger, I like that you don't have to take off the whole thing to take a look in and sweep, that was one of my concerns.