I have a hard believing you can get a 35 yr olds pair of k2 812s flat by hand tuning especially if you didn’t keep wax on them over the summer
Why are you even considering skiing in them?
The proper time to do a preseason tune is April
Then in November you scrape off the wax and they are flat with bevels are good to go
Leave them un tuned and dry over the summer especially if not temp controlled and no amount of hand tuning will make them skiable
if You French Fry when you should Pizza you are going to have a bad time