I would adjust the 913H to reduce the loft a bit. I think that may help fill the gap between your 4 iron and 4 wood a bit better.

Your result with the 24H is pretty much expected vs a 4 iron with the same loft.   5-10 yards more.    Still have a 20 yard gap to the 4 wood with the max distance. 

You CAN elect to drop the 4 iron and use the 4H depending on conditions. 

Have you thought about a 913F 21* fairway to fill the gap between the 4W and the 4H/4 iron?  May not be much benefit going to a 913H 21* vs the 24*.   A 7 wood is a nice club to navigate the fairways and hits off of some of the worst lies as well as plowing through the rough; it is also very accurate.

I have a gap of 20 yards between the 910F 19* (set at A2) and 910H 27* (set at D2).     What I do to cover it is choke down 1/2" on the fairway since I can't hit a 21H too well.  I used to have a  910F 24* and the difference in distance between it and the 27 was about 3 yards.

I used to have some G10s (15, 24,28, 32) using the steel shafts around the 2008 time frame.  I could hit them quite a ways (got about 165 with the 32, 180 with the 28, 190 with the 24 and about 220 with the 15 WHEN  I COULD HIT IT).  

The AP1 4 iron is 23 degree and the 4H (24 degree) matches the loft of the AP2/CB/MB irons.  Lou provided the assessment of the distance gain with the 4H. 

The Titleist 17 degree FW matches a 4 Wood.  You didn't mention if it was Titleist or another brand (loft may vary if it is).

I'd like to fill that distance a little closer to 190-200.  Your opitons include setting the 24 to 23.25, a 21H, or a 21FW or 19FW.  The 19 can be set back to 20.5, and the 21 moved to 20.25.  The biggest difference is increasing the loft will move the the head from 0.5 open to closed.  So the 19 and 21 adjusted up and down will hit differently.  A 21 H or FW (although I prefer my 21FW) set to 21.75 is another possibility.

In my case, a 15FW set back to 16.5 worked better than a 17FW because the dispersion was tighter.  With the face open I was getting too variable of a fade.  In your case, try the combinations on a range with a fitter, if you want to improve the distance gap from the 4I to the 4FW

Like Don, I prefer a 19 or 21 fairway over a hybrid.   I found out 7 years ago that I hit a fairway wood of those lofts much better than an equivalent hybrid.  The best I've done with a 20* hybrid is 180 yards and I have hit over 200 with a 7 wood.  On equally well hit shots, I hit a 21 fairway the same distance as a 17 hybrid. 

I've had the 910F 19* since last May.   I've got it modified to a 41" shaft length (I use a Winn Lite Dri Tac oversize grip to maintain the swingweight) and I use the 1.5* upright settings (D2, A2, D3, A3); the best settings.   The .75* upright settings (C2, B2, C3, B3) are fine off the fairway but horrible off the tee and I lose my balance on a downhill lie (I tried this for awhile to match a 9 wood that I previously carried and I had the same issue with it also).  The A3 setting was great off the tee and I got pretty deadly on the 170-190 yard par 3s but I often ended up using the 9 wood off the  fairway.  I recently re-set the 19F to A2 based on its performance off the grass at the range.  Found myself able to work the ball and can really smack it.  D2 worked OK but I tended to fade it a little.  I'm now getting used to A2 off the tee.