In September I will be building a paver brick patio, also during this time I will bring in some topsoil and grade approximately the last 50' of the yard from end to end. The grade done by the builder was a poor job and needs to be corrected. I have a couple of questions regarding the preparation of this area.The grass(weeds) were planted in the middle of May.I have a John Deer 755 with a bucket and a roto tiller for attachemets to use. 1.Should I rototill the area that I will be replacing or use a chemical to kill the existing weeds? 2.What type of attachment should I rent to spread out and grade the new soil,Gill Rake? Any suggestions on how to do this or products to work with will be appreciated. I wish to use Kentucky Bluegrass for a seed is my only decision at the moment.