I would read the Kennedy book and watch the Joe Balickie video before buying or trying anything. After watching th evideo 2-3 times, then reading the pertinent parts of the book a few times, you will have a great foundation.
There are a few little tricks to it, but you need to do a little scratching first before you can understand or appreciate them. But when you get going, all you have to do is ask here and we can help you with any snags you hit. Help is just a posting away!
I use tools almost exactly like Balickie and can't stand the Dembarts. BUT...the last shipment of W.E. Brownells cutters I got were total garbage. Gunline makes the same cutters and is supposed to be of better quality, so I will try them when I need to get more.
The one thing you must have is patience. And the second one thing you absolutely must have is the determination to do an excellent job and accept nothing less from yourself. If you have that one (OK, really two!) trait, then your very first job will eb a good one, and they will get better on down the line. I was looking at my first job about a month ago and it still looks good to me, even today. That was on a stock I made from the blank with less than $20 in tools. The checkering tools cost me almost that much, and I just held the stock in my lap as I sat in my recliner and watched TV-usually Seinfield. The point being, attitude and determination are waaaaaay more important than buying some cool looking tools and droping a lot of cash before you really know what you want.
I absolutely love checkering and find it one of the most relaxing things on this earth that I can do. I am just in a zone and can forget about everything else. Oh, sometimes I talk on the phone while checkering (with a blue tooth), but usually I put on my special "checkering music" and make diamonds.
Oh, on the lpi, I would not go coarser than 20 lpi myself. That is planty course enough and it posed no problem on my first job. Coarser than that and the checkering, even when well done, starts to look, well, coarse. 20 looks good on most guns that are not at a fairly high level.
Good luck!