I recently purchased this ski. Previous owner told me he only ran XPS mineral oil in it. I can not for the life of me find PWC mineral oil. I can find SNOW XPS mineral oil. I want to switch to full synthetic for ease of access to the oil. From my readings on here I am not sure if I should drain the whole system and bleed it with full synthetic or just wait till tank is low and then fill with full synthetic. My understanding is it will be fine to mix as long as both oils are XPS brand. My worry with this is I dont ride the ski much and worry about gelling. Also can I suck most of oil out of tank and add full synthetic instead of waiting for it to go down?