The International Cessna^® 170 Association

I have a vague recollection of reading a post on this forum about using a plastic wire tire cut down and used
as a dipstick to measure brake fluid level.

This may have a positive benefit of always keeping high level of brake fluid in cylinder and avoiding brake anomalies.

Can anyone add to the subject of checking fluid level in master cylinder w a simple dip stick?

I carry around a small plastic squeeze bottle with a built in capped funnel full of hydraulic oil plus enough tools to do,a major overhaul . I have a clean out every so often but this spanner could come in handy one day if you know what I mean. While I have never had to use the bottle for my aircraft there have been a number of situations where I have helped others.
My reservoirs are always full to over flowing .

I look in the hole at about a 45° angle. If I see fluid it's OK if I can't, it isn't.

I carry a small syringe with a long plastic nozzle on it (about 1"). Fill the cylinder then suck a bit out to be about 1/4" below the plug hole. They still seem to provide a fair amount of corrosion inhibition in the general area.

The fluid will eventually find its way out

I don't think you should be loosing that much fluid between Annuals. I you go from floats to skis and bleed them every time you will never run out!