I have never played an erquan erhu, and consider it unnecessary. Some years ago I put erquan strings on my second best erhu, and really liked the results. I suspect that the results will depend on the nature and quality of the erhu. After buying a zhonghu, I decided that the erquan strings were redundant, and restrung conventionally. I think it is better to have a backup erhu that you can use to try such things as erquan strings, than to get an erquan erhu.
Erquan Yinyue has a lot of very high passages that are hard or impossible to play on an inexpensive erhu. Of course, you can always play lower than indicated in the score.
Thank you David I was hoping you would weigh in as I have read many of your replies and threads on this forum. I think once I get to put on the strings and take them for a spin around the block I will know what I want to do. Unfortunately one cannot run to Guitar Center and figure this out. Grateful that this forum exist while I wait for my shipment.