I'm the same way when it comes to Shikakai if used in a paste. Even with other powders and cond. mixed in.
I can only handle it on my hair for about 10 mins. Even when mixed with cond. it's still too gritty for my liking, and hard too rinse out. My hair hates Aritha in any form. Now as for Shikakai in the poo bar or as a tea!
I think I have finally mastered a way of using this herb to make my hair thrive. For the past month or so I have been experimenting with a double tea rinse. The first one consists of Shikakai, Amla, and Kalpi tone, although sometimes I leave out the KT. I always use twice the amount of the other powders than I would the Shikakai. I steep it in a small sauce pan with the herbs in a strainer. I let this sit for about 1/2 hour. Then I pour it in a gallon pitcher and fill it up with cool water. After I rinse with this over and over I let it sit on my hair for about 5 min. then rinse it out. During the 5 mins. I quickly rinse out my strainer and pot, put on some fresh water for tea #2 and add Hibiscus, Fenugreek, Bhrami, and Bhringraj. If it's daytime I'll add the Horsetail and Nettle. If I'm adding Horsetail, I'll add double the amount.
I don't boil the tea, once again I steep it, dilute it, and rinse it through my hair. I DON'T RINSE THIS ONE OUT.
I gently wring out the hair and apply AM and Suave Humectant. (this technique doesn't work as well for me when I apply a protein cond. after tea rinsing.) I save those for when I make the pastes. I cover my hair with a plastic cap and let it marinate for about 2 hours with all these conditioning, moisturizing herbs and when I finally rinse....
It's a silkiness that's undeniable. Plus it feels clean and strong. I have been doing this once a week in rotation with the poo bar, and cond. paste. Imoan, make sure you have enough oil in your hair also. When I do the tea rinses my hair is coated in oil from a few days prior, plus I prepoo with more oil that day. Believe me the Shikakai will pull it off your hair , but if I don't go heavy enough on the oils.
Lol be careful because Shikakai and Aritha, especially Aritha will strip your hair down to the cortex.
Have fun but be careful with these two.
ETA: The silkiness I get from this lasts even when the hair dries, even before I apply any product or oil.