I don’t think Gandhi ever picked Nehru to be his successor in the decisive sense-he in fact wanted to disband the Congress party on Independence. Gandhi encouraged a broad field of leaders of all hues-including C Rajagopalachari (free-market believer), Sardar Patel (right-leaning conservative) and of course the left-leaning Nehru. Patel and Nehru were in a sense, like your nickname-Yin and Yang.
The tragedy was Patel’s death in 1950 left Nehru without a capable rival who had similar popular backing and administrative and political ability.
“he in fact wanted to disband the Congress party on Independence”
At the time of Indian independence, Congress for all practical purposed had dumped Gandhi altogether. And the reins of power were taken over by Nehru and Patel. Towards the end, Gandhi was his own man.....independent of the Congress party.