Winches were much larger ~35 years ago than they are on production boats today. My 41' boat has Lewmar 55-ST primaries; 42-ST everywhere else. There should be an aluminum support ring beneath the chromed-bronze feeder arm. The support ring remains stationary but it's inner (circular) surface slides over the drum as the winch rotates. These should be well greased with the lewmar grease or lithium grease so it does not bind/break while under load.
I would say that 2 wraps is insufficient; the loading can be much higher at the feeder arm than you think. The jaws of the ST will hold the line much tighter than the feeder arm can withstand; so if the line slips on the drum while grinding it the load on the line at the feeder arm could be as high as the sheet load at the clew of the sail. I have seen ST heads that the feeder arms are snapped off of; for the same reason.
If you are racing and constantly trimming you should not use the ST; just have someone tailing/holding the line and preventing over-rides. I would not feel too bad about the failure unless the owner had already told you not to use the ST without a minimum of 3 or 4 wraps. On my boat the rule is to have 4-5 wraps on the primaries because the line is thin (dyneema) and the drum is tall enough to accomodate the extra wraps. The line can practically fall off of the ST head without slipping on the drum with 5 wraps.