Pronunciation of "How" in Connected Speech

"How" is pronounced as /haʊ/. It's straightforward when it's said on its own. It's also easy to pronounce in sentences like:

• How would you feel about... → /haʊ wʊd/

But I find connected speech tricky at times. In the examples below, is the sound somehow softened or simply not pronounced in full?

• How old are you? → /haʊ oʊld/ → Two adjacent /ʊ/-like vowel sounds feel like a mouthful. Should I say /ha oʊld/ instead?

• How hard was it? → /haʊ hɑːrd/ → Here there are two consecutive harsh /h/ sounds.

• How is it? → /haʊ ɪz/ → Is a /w/ glide added between how and is, making it sound something like /haʊwɪz/?

Is there a connected speech rule that explains what's happening in these cases?

When I go to say those examples quickly, I often find I de-emphasize the following vowel. I still think I'm saying it, but I don't feel myself saying it very loudly.

The general advice I can find on online sites is that when there's a vowel after /aʊ/, insert the glide.

But I think there's more than one natural way to pronounce these in my Northeast American accent:

• How old (/aʊ/ followed by a rounded vowel):

  1. Elision: /ha oʊld/ ~ /haʊld/ is natural in quick speech, yes.
  2. Glide: /haʊwoʊld/ is natural, maybe the most common, but you don't want to emphasize the /w/ too much, just say it quickly. Otherwise it can sound like you're actually saying "wold" instead of "old".
  3. Glottal stop: /haʊʔoʊld/ — A glottal stop can be a natural way to "pronounce" the space in between words. It's understandable and lets you enunciate both words. But this is a slower way to say it; in fast speech I find myself using one of the other ways to pronounce it.

• How hard (/aʊ/ followed by /h/):

  1. Enunciated: I don't think our /h/ sounds sound very "harsh" to us, the way that velar or uvular fricatives would. You can just say it.
  2. Elided: in quick connected speech, if you say How 'ard /haʊ(w)ard/ I don't think it would sound odd at all, even if you don't usually drop initial /h/.

• How is (/aʊ/ followed by unrounded vowel): I agree that the glide /w/ is the natural way.