The one pictured is officially named AttiTude. It is hopefully the last slidehammer I'll build and probably #20 in a line of sliders built since 1967, beginning with one politely known as Oh F*** it's gonna move that employed a 43 pound deadblow and an axle from a Mack twinscrew. Deadblow definitely provides advantage in slidehammers eliminating the bounce inherent in solid hammers and translating that energy to work rather than recoil. Recoil delivers zero benefit.
OhF*** had the added ability to securely attach to the back end of a 20 ton hydraulic puller for those moments in time when a bit of shock impact got the job over the top and moving the way it should have gone. It also rode around on it's dedicated 2 wheel handtruck with ropes to tie it off to overhead structure when in use and a couple short ropes similar to lawnmower starting cords. Nobody wanted to slide the hammer more than 2 times, even with padded handles. Back in those ancient days of sliderules and Friden calculators a couple engineer types did some calculation and said OF*** delivered impact force similar to a 20mm cannon. I took their word for that.
A milwright company asked one day what I'd sell OhF*** for and I flippantly said 500 bucks. They were back an hour later with a check, and I didn't have to load it. As OSHA came on line the tool was declared unusable under all the new regulations, so the cart got enclosed with sheet metal so the tool couldn't be seen. To my knowledge the tool continued being used into 1985 when stress fractures in the flange retired it.
Been a good number of slidehammer based tools I've built since including self propelled prick punches using Ramset pins for replaceable tips and SlideSledge. I've come to love the deadblow system in many as Art Ritus sets into my hands and wrists. I've also put together a few deadblow knocking bars over the years for various jobs, and they too offer better results.
As to the question of shade spots and adult beverages, ya caught me. I was sitting comfortably on Absolutely Perfect Stool, under my beach umbrella (thanks to cardiac meds which are photoreactive) with a cold lemonaid watching the football players play. Counting part was easy, when I got to finger number 10, I employed my abacus system of moving welding rods in the can. It works well for an old guy.