I was wondering when I would hear from you.My opinion is that everyone should have electric assist as it extends your range.
I don't feel expert enough to say what type but I talked to Paul at 99 Bikes today who looks after my Trike and did an excellent rewiring of of it 8 months ago. He is of the opinion that it is a good set up but why don't you give him a call and tell him that he and I were discussing your potential conversion earlier today. My set up has a clutch and others don't they kick in assist as required while peddling. I have experienced riding that system also and it's pretty smooth ,but to be honest I am quite un sure on this issue other than to say a BIG YES to electric assist in general.