Half Marathon Effort in Week 18

For my long run in Week 18 training for a full marathon I’m considering an official half marathon. I’m doing the L1 50 or 55 mile week program so the distance is good for that weekend. What would be a good target pace or effort now that it’s taper time? Full marathon goal pace for all 13 miles or warm up for a few then maybe the final 10 at a goal pace? Something else? Thanks!