NO, I did not buy used off another bike. I own several old Hondas and experimented with what was on hand. I have since purchased new and am running with it. Don't assume facts that are not in evidence.
As to the pressures involved, I have no clue. The original xs switch was used on multiple bikes from twins to 1100cc inline fours. The Honda replacement is the same way, many different models including twins and fours.
On first start after installing the Honda switch, it shut off at about 12-1400 rpm. About the same as the original.
If you don't feel comfortable, shell out the big money for OEM Yamaha parts.