I've done both dry and wet cured pastrami from flats, points and beef rounds. There is no doubt this can make for some great pastrami. But...
...you can get some great results from a good quality store bought, already cured corned beef. There are some really great brands and there are some not so great brands.
The key in either process, store bought or home cured, and that's to make sure you get the salt leached out of the meat. I soak mine for several hours, rotating the water every 30 minutes. I even toss in cut potato or two during the process, because that helps remove the salt.