I find the electric pad saw which is like a large jig saw has worked well, but sometimes a handsaw works better, and also the Scorpion saw, and the chainsaw, the latter is officially called a lopper, and on a long pole is unwieldy to handle, but does cut well.
A table saw would likely be best, but in the real world what we are looking at is what is to hand.
The planner will get rid of imperfections, as will a belt sander, but latter is slower.
I had the same problem laying slabs, do I start at house and work to steps, or start at steps and work to house, and what to do with the sliver of area left over, I filled with stone.
Even a drill attachment circular saw will likely cut it, but more down to what you have to hand, than what will do the job. This

from Lidi has been a god save for me, but hardly worth getting for one job.