Those (53 & 70) are pretty heavy especially if you don't have experience with KBs. I'd start out buying two 35lbs KBs. That way you can start off with using one for swings and snatches, cleans, etc.. and work up to doing two handed snatches, two handed cleans, etc...
I wouldn't focus on heavy weight with KBs (especially starting out). Work on getting good form and then work on explosiveness (speed). You can up the reps and do the exercises in circuit form to up the intensity.
Buying such heavy KB will limit you exercises
Just my two cents.