Checking fluid level on trim pump

[crazy charlie]

Hi guys.I am having a brain fart on checking my trim fluid level.I havent had any issues or need to check in many years. 1989 mercruiser alphas with opaque resevoir.Cap w/o dipstick.No issues except that they seem to be raising and lowering slower than in the past.I think i remember checking with drives full down position .Where should the fluid/oil level be ?? Charlie