First, I like to get a deep cut with a high-speed, powerful handheld grinder equipped with a shroud. Remember to predict the amount of exposure you will have on the rest of the floor and try to match this with your edge. Your floor can look terrible if you have big aggregate exposure throughout the central part of the floor and a salt and pepper finish on your edges. This first edge step is as crucial as it is with your big machines out on the floor. Your goal is to "flatten" as much as possible, eliminate as much surface defect as you can and refine the edge in preparation for the resin pads. A note to beginners: Be very careful on this step! You can create a lot of damage and headache in a very short time yielding a high speed hand grinder. The dreaded "ring mark" or "grinder scar" will have you crying in your coffee later in the polishing process
I recommend using a high-quality, 24-segment metal cup wheel of about 80/100 grit if possible. On a technical note, make sure you do not just keep the grinder up against the wall while you proceed or you will have a 7-inch line cut into the floor from the cup wheel. You need to keep the grinder moving in a circular motion to eliminate this. This step can be done before or after your first pass with your grinder. I prefer to do it first so your grinder can eliminate as much of the profile/damage from your initial edge cut.
As your floor progresses through the process, it is best to try to keep up with the grit sequence of your polishing machine. Again, high quality resin pads are essential. We like to use a variable speed 7 inch grinder with 5 inch resin pads. We stock low grit resins such as 30 and 50 grits which are essential to follow your metal pass.
I should note that the starting grit is determined by the degree of cut you are trying to achieve. With a cream polish you would not start with a cup wheel. For example, some contractors start with a flexible copper abrasive to follow the floor and never use a cup unless they are going for aggregate.
Essentially the process along the edge is the same as what is happening out on the main part of your floor. I think something to remember would be as you practice full refinement as the CPAA teaches, the edges need to be refined fully as well.
Well defined edges that match in aggregate and tone with the rest of the floor takes a lot of work and craftsmanship. You are battling the whole time trying to match the refinement of a heavy machine with much more down pressure than your variable speed hand grinder. As I say with anything in this business, you should slowly refine your process and research the "new" edging solutions and equipment before you rush out to buy what they are selling.