Dealt with this last year as my boys wouldn't pike enough to start it up. Many gyms seem to do a leg lift to bar before kicking back to arch and judges weren't taking for going beyond the 90 degree hip angle when I think pike according to the routines.
It would have helped if my boys were simply stronger so they wouldn't pike as much. Leg lifts to bar extend to candlestick or tapping straight body lifts to candlestick ( kind of like raising through front lever on rings from hang ).
I haven't coached boys for years, but the one thing I did then which I still do with the girls is "chin-candle-chin-pullovers" instead of pullovers or pull-ups. They train pull-ups separately. I make them do the pullover after they are already in the candle.
I think that there is a fundamental "flipping" action (using the entire body) that the kids pick up on when they do those correctly. It may help the boys get into the right position to counterswing better.