The three-match Test series is due to get underway on December 26 in Centurion.
Rahul also hinted that the choice among Ajinkya Rahane, Shreyas Iyer, and Hanuma Vihari for the number five slot is a tough one. While Rahane has been struggling for runs lately, Iyer is coming into the series on the back of a memorable debut against New Zealand at home.
"Every team wants to pick up 20 wickets to win a Test match. We have used that tactic and it has helped us in every Test match that we have played away," Rahul said during a virtual media interaction on Friday (December 24).
"Workload also becomes slightly easier to manage with five bowlers and when you have that kind of quality (in Indian ranks), I think, we might as well use it," he added.
Veteran pacer Ishan Sharma looked off-colour in the recent home series against New Zealand, and the team management might prefer Shardul Thakur in the line-up because of his superior batting skills.
When it comes to the batting line-up, Rahul, Mayank Agarwal, Cheteshwar Pujara, Virat Kohli and Rishabh Pant select themselves while one among Iyer, Rahane, and Hanuma Vihari will get a look in.
"It is a very difficult decision to make obviously. Speaking about Ajinkya, he has been an important member of the Test team, played very, very crucial knocks in his career," Rahul remarked.
"In the last 15-18 months, he has played some crucial knocks, that partnership with Pujara at Lord's, was important for us in winning the Test match.
"Shreyas, obviously has taken his chances and got a brilliant hundred (along with a fifty) in Kanpur and he is very exciting. Hanuma has done the same for us, so it's a tough decision. We will start having a chat today or tomorrow and you will get to know in a couple of days time."
According to Rahul, the bounce in South African tracks isn't similar to that in Australia.
"It's pace and bounce in pitches here which is very different to every other country. We have come early and tried to get adjusted as it has been a great week of preparation.
"Sometimes pitches can be a bit different because of its tennis ball bounce. In Australia, pitches can be fast and bouncy. We have had a lot of sessions and we are trying to understand and adjust to the conditions."
Rahul will perform the role of Virat Kohli’s deputy in the Test series against South Africa in absence of an injured Rohit Sharma.
"I have always enjoyed responsibility and as an opener, we have responsibility for providing good starts. Now, maybe a bit more involvement with regards to making strategy with the captain. Maybe pass on some more information and take some pressure off Virat."
For Rahul, the key to success is keeping things simple and not overthinking.
"I don't think too much and put myself under pressure that since I have performed in England, I have to do well here and what if I don't do well over here," he said.
KL Rahul is keen to replicate the good showing of England tour in South Africa.
"What I have in my hands is to prepare in the best possible manner and give myself that chance. My preparation has been good. Not just me but everyone had a good time, so we are all excited.
"I would try to replicate my form in England and give my team a good start, get through that new ball and hopefully, I can continue that form," he concluded.
(With PTI inputs)