I spoke with Dr Borody a couple of months ago and he suggested using 100-150ml particularly if the entire colon is affected. It sounds like your husband is flaring right now? I think FT works better if a person is not flaring. Some protocols recommend going on prednisone to reduce the inflammation and number of BMs to give the enema bacteria chance to colonize. I don't know if this is a possibility with your husband. The longer he can hold the enema the better.
It's good that you are elevating the body as it is important to get the enema to where it needs to be. You should try to elevate even more than you are doing. We use a mattress with one end resting on the side of the bed. I only blend for 3-4 seconds. I don't think the strainer needs to be a fine one. Maybe a courser one will allow for a thicker mixture and therefore more good bacteria.
I really hope FT helps your husband. It has proven to be a very long process with my son and right now he is doing very well. I hope it continues.
Good luck and let me know if you have any more questions.