You have to look at the head weights. Your #5 hybrid is about the weight of a standard 4 iron, so you should need to trim it to the #4 iron trim, which is 1/2″ from the tip. The #6 hybrid is about the standard weight of a of a #5 iron, so you would trim it 1″ and the #7 hybrid is approximately the head weight of a #6 iron so you would trim it 1 1/2″. So, the head weights do correlate with an iron head weight and that can guide the trim. However, you are making these particular hybrids longer than what the correlating iron club lengths will be. In theory that would not matter with regards to the flex (they would just progress at a different point on the chart). In other words if the frequency was say 302 cpm at 38″ (normal #5 iron length) which is in the R flex range, it would be approximately 290 at 39.5″ if nothing is done to the head weight. 290 at 39.5″ is still an R flex at that length. So the flex should hold at the build you are describing. That being said, the longer length might make the clubs feel a little heavier and more flexible than the iron counterparts at the normal iron lengths. Might not, but might. Generally that is what we see.