Robert,
Following the radial on either the VOR or GPS in OBS mode is a practical way to go, but to answer your question, it is also possible to get the exact clearance into the 430W/Entegra in the Cirrus without too much fuss.
Since "RV to join the IRW-166 radial, to the the ADM-321 radial, ADM" is a typical southbound departure from the OKC area and setting up well can reduce inflight workload, you may want to create a user-wpt at the IRW-166/ADM-321 intersection (on user wpt page; takes 30-sec or less on batt2 prior to engine start in a Cirrus). Once you have the wpt, the flight plan is PWA, IRW, IRW16 (user wpt), ADM... Scroll down to IRW16, press menu, and select "Activate Leg" for guidance to join the IRW-166 radial rather than direct IRW.
The magenta line and HSI will show how well the vectors are working to join the IRW-166 radial. Once cleared to join, you can select HDG with GPSS armed on the AP. Your GPS+AP will auto-sequence through the whole flight-plan following the depiction on the Entegra and 430W without further intervention.
--
Craig (CFII/MEI at PWA)
http://AwlBiz.com/fly
