Sorry -Didn’t notice that you might want AMBER bulbs.
Re-Googled “short amber 1157 bulb” and got this:
https://www.ebay.com/itm/33432...j4erFdhoC8J4QAvD_BwE
“The answers are out there”
BTW, @JoelP I had a similar problem 25 years ago when I installed year-correct 356 front directional lenses, which happen to be milky colored and quite shallow. I needed a short, single-filament, amber bulb and scrounged around every Mom N Pop auto parts store in my area until I found them and then bought out all they had (12) thinking I would never see them again. Still got 10 spares.
Ed’s post is good, too - Motorcycles use many of the same bulbs, just shorter, and those are available in LED versions, too.
One last thing - If you go the LED route for directional bulbs (because they are brighter and [supposedly] last longer), that’s fine, but often the LEDs don’t draw enough current to keep the flasher relay happy and they won’t flash. The answer is to get a different flasher that works with LED bulbs or, as I did, keep the same flasher and install 5 watt ballast resistors in parallel with the led bulbs to fake out the flasher and make it flash with the LED bulbs. Those resistors are available at Autozone/Advance/NAPA/O’Reilly auto parts.
Hope this helps…..