You'll want a thin PCB for the LEDs to be able emit light in a pattern as close as possible to the filament in a halogen bulb. Here's the video I watched when shopping for LED bulbs for a CN7: https://m.youtube.com/watch?v=nnD_sDWNjEw
Thank you, very informative videos! Incidentally, I've been recommended the DD SL2 Pro with a DD canbus anti-flicker module by a local shop. The video gives high praise to the SL1, so I'm hopeful the SL 2 will be better!
EDIT: I just purchased the SL2, will update the main post once they are installed!