I bought 1156 and 1157 replacements from
https://www.superbrightleds.com/. Amber, Red, Natural White for the appropriate slot.
I use these in my 914, too, with a modified flasher from
https://www.spokeworksled.com/ Work fine in the 914, no probs.
My 968 is doing goofy stuff, too. When I did just the rear turn signals I had a hyperflash. When I did the front ones, too, the t/s lights just stayed on.
I'm going to try another couple flasher relays to see if I can get it working. If not, I'll put incandescent back into the t/s slots.