Italian small round amber side marker /turn signal lights - 280SL

[pandachuck]

Our recently acquired 280SL Pagoda was originally sold in Italy.
Therefore, it has the amber small round side marker / turn signal lights, but these are currently not connected (there is currently one loose wire at each side), and the light bulbs are missing ...

I have a few questions and hope someone may be able to help
(1) based on other posts on similar topics, there appears to be some debate as to whether these should flash in sync with the front/tail light turn signals or not (and instead come on without flashing when parked). Based on Italian/European rules at the time, it appears the original intent is to be flashing in sync with turn signals. Any thoughts on that?
(2) anyone has the instructions or knows where to find the instructions for the correct wiring of these signal lights?
(3) anyone has suggestions on where to find the correct light bulbs? I have included some pictures of the current connectors, which are mostly clear plastic. There are some posts from 2010-2011 in the Pagoda SL Group, and they suggest that the light bulbs can be found from MrFiat (because these were required on all Italian cars at the time), but the links to that website are no longer working.
(4) finally, there are also some posts indicating one should not use LED lights for these, because there needs to be a resistor for these side markers / turn signal lights to work. Anyone can shed more light on that?

Thanks!

[Pawel66]

Perhaps these are the bulbs: https://mrfiat.com/fiat-500-600-850-1100-1300-124-side-marker-12-v-5-w-bulb.html

I think, to be honest, they are pretty standard bayonette type bulbs quite widely available, but maybe I am wrong:
https://esklep.pesta.com.pl/zarowka-12v-5w-bc-t10-narva--2264#nclid=b2e354fcfe66eb6f6c166ad78881b509

Or here: https://www.sls-hh-shop.de/main/en/mercedes-r170-slk-first-generation-82-lighting-wipers-heater-c-4154_4156/instrument-panel-bulb-12v-5w-w2-1x9-5d-p-135184

Those also come orange, some of the blinker lenses (including the Fiat ones) were white.

And let me risk this:
- I would just wire them parallel to front blinkers
- if they slow down the blinking rate, I would just put 12V LEDs there (although those have resistor too), I would have thought resistance may not be required if wired in parallel; if you have ordinary LED, you need to add resistor indeed

But someone will verify.