We've recently taken in a 3 year old whippet. We've only had greyhounds as far as sight hounds, so the whippet world is new. Wondering what your favorite collar is. For our Greys, we always do a martingale with a tag collar. She came to us with a thick leather whippet collar. She was surrendered because she escapes a lot, so the idea of a tag collar doesn't make me comfortable. I'm not sure of we should keep the thick leather collar and use a martingale for walking or what the best plan is.
I think whippet collars are so pretty on them, but, I'd go with a martingale for a known "runner". At least for walks or outings, until you have a better feel for how she'll react to different stimuli. Plus, they're easy to make if you sew- and cheap to buy if you don't- so you can have so many fun ones in her wardrobe.
I bet you have a fun crew with all of those graceful necks! We use 2-3" wide martingales with our Dane, she has such a thick neck and slippery floppy ears, there's no safe substitute, she can just shake a normal collar off unless it's unsafely tight.