I went with 14" bars on my deluxe, thought about 10-12" just for the easier installation. I was told that I could have put 10-12" bars on with only swapping out the break line by a mechanic at the Harley shop.
Since the shop wanted about $1200 bucks to put the 14" bars on I decided to do the install myself. Took me about three days but wasn't that complicated, I could probably cut that time down to half the second time around.

 

I just installed Carlini 14's and went +8" on brake, throttle and throttle return cables. It was a perfect fit. My bars also run about 1' higher than 14". I also soldered my own wiring and did 15" extensions in case someone wanted to go insane down the road and add 20" apes or something. lol.

 

I actually did the work on my bar swap. 14" Carlini Flying apes with High Roller risers. I went +8 on throttle/idle/brake; +10 on clutch and everything worked out real nice. I went with Harley Davidson cables. Tried Magnum Shielding and they were a nightmare. Do yourself a favor and go with HD cables if you have to swap out. A significant cut above Magnum Shielding. Get a service manual, most important. And don't just take anybody's word here blindly especially if you're new to these parts. There are some here who's info is invaluable and they have helped me out immensely. Then there are those who play the part.

Now here is the bad news. I had to try a couple of different lengths to come up with what I liked. To save yourself this agony you can do like Tampa and just drop your bike off at the Harley shop. Then come back here and give out advice to those asking for info pertaining to a bar swap like an OG.

 

Yes it would depend on width. Have done two bar swaps on Fatboys using short risers and 10" bars with 32" width and 5" pullback. Both got by with stock cables (barely), both needed a new brake line. Any more width would have required new cables, good catch.

 

I used Magnum Cables and had no problems at all. I used their website to order up the correct lengths (after measuring before ordering) in their Black Pearl series and everything went together perfectly.

 

Went together for me real nicely too. Until I tried to remove the T/I cables from the swith housings to use a different length.

OP, FLS103 was on the $$$. 10" apes are what you are looking for.