Bought the bike last spring, dealer talked me into progressive shocks(4) to lower bike, Mustang seat to lower bike. At 5'8" i still am not flat footed.
Fatbaggers has a seat pan lowering kit,($2800 installed). do i go for it or say screwit and go back to a Heritage Softail???? over 30K so far and I still slip on crappy roadways.

 

There are more options. First of all, tell us what the center to center on your shocks is, with them installed. I just lowered a 2013 for a customer but it was done on the FACTORY air shocks. He had the bike lowered at the dealer with the streetglide shocks, but it wasn't enough. I do a custom disassembly of the factory shocks, and cut and lower them. Wound up being an 11.5" shock installed and now he is good (at 5'2")
Right now his lowered bike is 1/2" lower than the "new" Harley UltraLow... though I did nothing to make the primary cover narrower a-la UltraLow.... but he doesn't need that.

As always, YMMV

 

wear platform style boots it sure helped my runt buddy

 

In addition to thicker soles on the boots, I would research seats.

I know you bought a Mustang, but from my research, they don't bode well for those of a lesser stature.

I bought my wife a Danny Gray Speed Cradle solo for her 14 Street Glide Special... she's 5'2"

 

You might want to look at boots and seats as others have recommended. I'm 5'6", but with a 30" inseam. I could not flatfoot my 2010 Limited, so I dropped the bike 1" front and rear using Progressive cartridges and 944's. I also went to a Sundowner seat, which lowered my butt and motorcycle boots with a 1" heel. After all this, I easily flatfoot the bike and have no problems walking it around in parking lots.

 

I am 5' 8" with a 30 inch inseam. I can flat foot my 2014 Limited by wearing my Red Wing 968 Engineer Boots. My next step, had I needed, would have been to have the seat lowered by Mean City Cycles. But the boots did the trick for me.

 

I want to say "that's odd", because I'm 5'8" & flat foot my '14 Limited. My only issue is walking it around; my leg hits the primary.

But we're all built different I guess. I would recommend you find a dealer that has '15 Ultra Low or Limited Low in stock & try sitting on that for fit. I believe you can duplicate that entire set-up on your Limited to include the new, more narrow primary cover if you would want to. (The new Lows have different handlebars too, but that shouldn't have anything to do with your issue.)

Are you wearing motorcycle boots while riding, with good tread on the bottom? As others mentioned, having a shoe cobbler add thickness to the heel & sole can help too - I've seen others do that.

Good luck!

 

Imo, flat-footing is overrated. But then again, I don't ride 2-up much. I can't remember the last time I had both feet on the ground at the same time while on the bike. As long as you can support the bike well and are comfortable with slow-speed maneuvering, you don't really need to worry about flat-footing it.

 

I find it a bit helpful (or at least convenient) at times to be able to push the bike backwards with my feet, it was a bit more challenging to do when I couldn't quite flat foot.

 

I'm also have a 30" inseam, 07 ultra, all I have done was sent my seat to Mean City Cycles for mod and I wear logger boots most of the time.
All is good