I agree with HondaGalToo, a decent chain breaker tool with riveting capability will pay for itself. I wouldn't have a tool box without one. Also, excellent advise on how to remove the counter shaft sprocket, do not use the gear box, use the rear brake.
If you choose to use an angle grinder to remove the old chain, you're still stuck with the installation of the new chain. You can either go with a clipped master link (not good), have your dealer do the install or go out and buy the tool. Remember, unless you happen to buy a chain that is the exact length, you may have to remove a few links to get it to fit.
The clip vs rivet master link debate has been on going and it's up to you to decide what you want. I've never had a master link clip fail when motorcycles used to always come with them. For many years of riding in the dirt, I've always had the clip type, when cleaning the chain it's more convenient to remove the chain from the bike.
But now, I always rivet the chain on every bike I own. If you've seen the damage a loose chain can do at speed, even if you've been lucky up to now, you'll rivet your chain. For a street bike it makes sense and hp/torque of the motor doesn't make that much difference on whether or not the clip will fail.
My opinion is, most people don't maintain their clip. And, when removing/installing the clip they use a screw driver or something similar and twist it off. Or worse, they install it backwards. Should you decide to go with a clip type, don't install it and forget it. After removing it a few times, replace it, they're cheap.