Don't cheap out on blades either - it'll make your life miserable. Ask me how I know that one ...
Highly recommend DeWalt blades. Use a good oil to keep the blade lubed and cool too. Not crappy WD-40 - about the only good use for that garbage these days is shining up plastic on dirt bikes and ATV's. They cheaped out on the formulation some time in the early 90's. It's been absolute garbage since.
Here's a few pics of my coil install on my Mark III.
Another word of advise: DO NOT buy coils from Hilkoil - guy is a CROOK!
You can search out my multi-page threads on that topic ....
Anyway, here's the pics. I joined two coils together in series. I angled them to help natural convection flow without using a circulator. Started with small pilot holes, then drilled them bigger:
After just 3 minutes of cutting with a cheap blade .. also from Hilkoil, surprise surprise ...
Three holes cut, and you can still read the logo!!
These coils ended up corroding away to nothing. I have a different set in there now that worked great for 4 seasons. Now I have a stoker boiler, so they're on standby.