The correct way to check the static internal lines and equipment is to perform the required bi-annual transponder Mode-C reporting and TSO'd altimeter concordance tests by an avionics shop.  BTW, it is good practice to do this check and log it before the first flight in a newly certificated experimental, if possible.

 

Flush static ports work just fine if they are located in a tested and recommended area (like on the 300 series) of quiet air.  Furthermore, one on each side (then T-ed together) is cheap insurance that a single port opening or line low spot isn't blocked.