I thought someone might go there...since we bought the boat last year, the Admiral made it clear she would like the grayed toe rail varnished which at this point probably means getting it replaced as it is probably original. This is a pretty strong push from the Admiral, so I am looking into it this winter. (I’m sure I will need to take another mortgage out on the house)
Toe rails are a special circumstance when it comes to varnish. Depending on the design of the toe rail it can be difficult if not impossible to fully seal the teak which allows water to wick up under the varnish. It quickly turns color and peels off. Sabre sailboats are notorious for the issue which frustrates many owners and sparks "varnish wars" on a Sabre list.
Toe rails are often partially submerged when the boat is heeling which is part of the problem as water can then wick under the varnish. One solution to the problem is Cetol Natural teak. The color is close to acceptable and the finish is porous, thus any water wicking under the varnish can evaporate. This is not the orange Cetol which is quite deserving of vitriol due to its color.
Another option which I will probably try next spring is Semco Teak finish. Reportedly, this finish is not subject to peeling and does not support mold growth that oil does. Maintenance of Semco is fairly easy and inexpensive.
Before spending heavily on new teak rails do some research to make certain water can't wick up under the varnish. If the rails have not been varnished by the PO who loved varnish, there is a reason.