MR816 with external FX processor: DI needed?

Hi,

I’m currently processing tracks in Cubase by sending them to a Yamaha SPX990 and returning them via I/O 3 & 4.

I get a headache whenever trying to sort out impedance, balance and line/mic level issues, so I just put a DI between the SPX’s outs and the MR816’s 3 & 4 ins.

Soundwise everything seems OK, but I wanted to know if this is the correct procedure?