When I put my rootlets in last year, I used a narrow shovel, drove it in at a 45 degree angle, opened the cut just enough to insert the 3 year old rootlet to the desired depth and pulled the spade out. then I stepped on the cut, and moved on. Used woods mulch to cover, and when on to the next one. I didn't rake at all, just drove the spade in thru the 1\" of woods mulch. Got excellent results.
I'm sure that if you manicure the beds like you've posted, you'll get good results as well. My method was inherantly quick, as there was no raking.