I also recently got a CU300 Smart. I am using a temporary 4" from my 6" drop to the saw port, until I have time to hook up some 5" pipe to the 6" drop. Works ok, but could be better. Haven't gotten around to the over the blade part yet, but I am wondering about using a shop vac to the small factory blade guard.

Have you tried that yet? I will get around to trying it in about a month, but just wondering if you already have.