So during my hybrid 'transition'.... I wanted to just start out with the 3 IST, 20° and 6 IST, 29°. I have not reached for my 4 or 5 iron since those two hit the bag. I have been able to dial up or down and get those clubs to fill some giant gaps. I think the 4, 6 combo would be even better, maintaining a steadier swing to control distances. Keeping the 4 and 6 IST in the bag would allow an extra wedge or maybe a 7 wood.
My biggest fear was a bounding ball into a green that wouldn't stop. With the added height the IST give me, stopping power is excellent.
As a side note the flight of these is very straight. Yet its easy to hit a giant draw from under a tree limb or slide a fade into a tucked pin. I only have 4 rounds with these, I'm continually in awe of how versatile they have been. I'll complete the bag with the 4 and 5, but I'm not convinced it necessary to carry them all.