Hello Rubin,
The color of my OT1600 is an original color for the Fiat 850 in the sixties.
Sabbia beige 583 and it's also used by Lada!!
You're going to make a OT2000 and they were white. you can see that on a photo of the Japanese collector of abarth.
They are standing next to eachother, the OT1600 and OT2000
Looking at the interieur of your 850TC, I would choose the bleu color allready on the car. That is looking great too!!!
A frind of mine had an 850TC replica and made the color himself. Unfortunetely I cannot ask him what he did with the color he passed away 10 years ago.
Good luck with finding or making the color for the 850TC!!!!
Groet,
Fred