I have a friend with one thumb. The other thumb was lost between the chain and rear sprocket while cleaning the chain with a rag and the bike in first gear, running while on the centerstand. The rag got caught between the sprocket and chain and his thumb went around the rear sprocket, but didn't come out the other side. It wasn't a pretty sight. Do what you wish at your own peril. Racer
Most of these pumps are all the same, just different packaging around the pump. Just buy a cheap one and remove the case the pump is enclosed in. I think I paid nine bucks for mine at Tractor Supply.
Not to state the obvious, but I see a lot of bolts and push pins under there that could be used as mounting points. Use what's there and keep it simple. No need to add more weight and spend more money. Racer