There are many things to think about. The following is heavily edited from something I wrote elsewhere:
First, be aware that there is a lot more to police DT's than there is to self defence. You have to be intimately familiar with Use of Force justification, relevant case and state law and the department's policies, procedures and Force Continuum. You need to thoroughly understand and integrate all the force options available to the officer (OC, ASP, PR-24, tactical folder, taser, back-up, sidearm and radio). You also should be familiar with all the common restraint devices (handcuffs, flexcuff and hobble).
That sounds like a huge amount of information, but it is the context of the job that makes it so difficult for outsiders to teach.
A small and specific course that centers on your strengths is a good place to start. Get a DT/Use of Force Instructor to go over the material with an eye to the aspects mentioned above. Get a red weapon and a duty belt and practice with respect to weapon retention and modifying techniques (ukemi in duty belts can really ******!) And be aware of things that don't apply (ie breaking a turtle is almost never appropriate.)
End of old information. I would suggest working with one of their present DT instructors, building the curriculum around skills they already posess. Adding a few principles that will help them adapt. Staying very focussed on the tactical needs of the officers (It's not a game, and a lot of the win/lose mindset has to be jettisoned... there are lots of weapons in reach... will the threats friends arrive before backup... etc.)
I've designed a 4hr block for my people. You can reach me at:firstname.lastname@example.org
if you'd like to see it.