I have skews from 1 1/8" down to 1/8",square round and oval,the size of the skew depends on the size of the stuff your working on,I use the 1/8" skew on micro goblets with captive rings(5 mm tall)up to the big ones on say my latest piece which is a totem pole (japanese style)4-7" across and 13 ft tall.Practice is the only way to master these tools and dig ins can be spectacular,(had to have a week and a half of turning sliced/mashed finger),just got back to it this week with no probs,but remember,concentrate at all times when using these,it only takes a millisecond lapse to get a dig in,also you can use both points to work with,long point for cleaning end grain,short one for shoulders on square work,planing use the bottom third I`d say,cheers,
Eric.