Re: Practical internal training ?
Ueshiba had this in his repertoire, and demonstrated its effects on his students, it's just that he did not include it in the curriculum he taught. So, you will have to go outside of aikido to get it. Taiji and related Chinese arts with substantial internal components include it as part of their curriculum, and they are easier to access than the Japanese arts that traditionally use them, such as koryu jujutsu. So, you may even need to go outside Japanese MAs to get a good internal foundation.