The reason I suggest the Red 7 count is because it eliminates the need to convert the running count to a true count.
The truth is that once you learn how to use your chosen counting system, you won’t have any trouble making the conversion required in a system like the hi lo, so the system isn’t as important as learning how to use it without making mistakes. Each card in the deck is assigned a number. Some cards are +1, some cards are -1, and some cards are 0. As you see cards, you add or subtract the number assigned to them to or from your running count. Most running counts start at zero, but if you don’t like to use negative numbers, you can adjust your starting count to 10.
Once you choose your system and assign the numbers to each card, start practicing with a single deck of cards. Flip cards over one at a time and keep your running count. Keep practicing until you can keep the count while turning the cards over as fast as possible. Then add more decks of cards until you can count down an eight-deck shoe as fast as you can turn the cards over. The next step is to turn the cards over in two, three, and four card hands, keep doing this until you have the running count mastered. This doesn’t take as long as you might think. With just a few hours of practice, you can learn to keep the running count well. One quick tip is that when you turn cards over in hand sizes, you learn the high and low cards cancel out, so you just treat them as zero.