**Is ther any real reason to NOT put reverse risers in a Javelin??? **
Yes, I think there is. The risers are made for a PDF rig ! The D-ring (I think it's called this way) on a PDF rig is attached higher than de D ring on a javelin. This would make it more difficult or impossible to cut away with a malfunction which doesn't put you up straight (on the javelin with reverse pdf risers).
Because of the lower D-ring, the risers get ''stuck'' in this situation.
You can test this on the ground. Put the reverse risers on the javelin. Let somebody else pull the risers backwards with some force and try to release.
So, don't use the PDF reverse risers on any other rig then a PDF rig !