If your approach does not include radar interferometry or polarimetry, I suggest to use GRD products then. SLC data contains phase information at slant resolution, but after pre-processing, you end up with a ground resolution of at least 10 by 10 meters which is identical to what you can download as GRD product. This would save you a lot of downloading and processing time.
In this post, standard pre-processing procedures are suggested: Radiometric & Geometric Correction Workflow