Clicker training addiction part II

I had written previously how my cat, Bootsie, is addicted to clicker training.  Now she purrs during the sessions and moves rapidly through her routine.  We have to do a quick routine first thing in the morning and then a second more involved routine in the evening. I am sure I am the one who has been trained.

 Now, I was wondering if any readers have had experience with feral cats?  There is a colony in the industrial area where my company is located.  I have been providing food.  I have also TNR'd (trapped, neutered, released) 5 so far.  I also had all of them vaccinated.  Most of this was done at my own expense.  I did get some assistance from our local Humane Society for the spaying.  There are probably 3 more to catch, but so far they have eluded the trap.  I will eventually get them.

 These are healthy, very good looking cats.  One calico waits for me at feeding time.  We've done the eyeblink thing back and forth, but she keeps her distance.  The flight distance has been gradually decreasing.  I had TNR'd her late last year. 

 I personally cannot take another cat home. So, I would not be able to rehabilitate this cat if that could even be done. I believe in monogamous relationships with cats, but I am glad that there are people who can successfully take care of and provide enough love for multiple cats.  It would be too hard on my cat to have another cat around.

I will say this in defense of feral cats.  We do not have a rodent and pigeon problem.  Rodents have done damage to paper files and equipment in the past.  When this colony moved in, all those problems disappeared. I love these cats and want to do all I can to help them.  Any suggestions or comments?

 Thanks.