To kneel on something besides the concrete is really important. I used knee pads for a while, they were kind of a pain, uncomfortable, you have to make an effort to put them on, so often they were ignored. I started making matts from the foam they wrap a new bumper in, that works good. A carpet like this from the trunk of a total are nice.
I don't let a total leave the shop with one and have made sure every tech has one.
A quality creeper is a must. I have one of these Lisle low profile ones. They are the only way to fly if you ask me.
On that spot weld drilling, I am sorry but there is NO WAY I am going to work without a Spitsnagle spot weld drill.
There is simply NO WAY I am going to work without it. You can remove a spot weld with virtually zero cut into the metal below. You use next to zero effort because it's bit is pushed into the metal by air! You simply place the tool in place and pull the trigger and it does all the work for you. You dial in the depth to go and wham, you can drill hole after hole in perfection.
Start buying quality tools that save your back, you will be very thankful in twenty or thirty years.
Brian