Going in increments of 25% and so on won't hurt anything but I would just go the flush route myself. I'll get those contacts for you today and pm you

 

Be carfull just switching strait over as you can unseat your rings. Have seen it happen befor if you do be easy on it for a while. Another thing is they clame you can run the oil longer with synthetic but synthetic can't stop contamination like moistur and fuel from getting into your negin so it is still good to chang you oilon a regular scedual