Heatsinking A 1.8A Mohgasm Driver

I have just received 8 of these copper heatsinks from dx, ~$5 and I want to build a m140 445nm build in a c2 host, and I was wondering if this heatsink for a 1.8A mohgasm round driver is good enough. I will have to round the corners so that it fits into the pill. This is the largest I could find.

That's will be good enough for a decent duty cycle (assuming a 2 cell build)

Make sure it fits in the pill before you epoxy it to the driver

It's about the best using as much copper as you can. GJ