I have experience with health topics but do not consider myself an expert, so I would also follow up this line of thought with others like the barefoot herbalist ect.
In my experience of using these herbal substances, the psyillium is a fine adjunct to a constipation situation. It is safe and tho perhaps minimally scouring of intestinal health,can be used multiple times in a day, since it is cellulose we arent able to digest it so it stays in the GI tract, absorbs liquids to a large degree and thus mimics a fiberous meal and all that that would entail , so being very helpful for temporarily ending constipation.
The senna, tho, is fairly stressfull to the GI menbrane and is also potentially painfull to deal with so caution to avoid overdosing the patient and causing gripping pains needs to be of concern, but it is very helpful to remove built up intestinal matter ect.
I am of the school of thought that relies on food combining and ripe fruit as the main item in diet, and this helps alleviate and reverse congesting eating habits along with aiding quick reversal of intestinal complaints.
Arnold Ehret, the Lust family and B. Szekley's books are quides that have helped my research in this area.
I think your attempts with the castor oil packs are important because many of us relate to our health ailments so symptomatically that unless we are ready to really change our diet long term, our deeper congestion, organ and cellular wont be relieved and our health will never really be what it can.