You can buy heel cups and put them under the insole to give you some extra lift. I did that with some Cliftons for an achilles issue....

I never thought there much much limitation in the 10 mm drop world, weird.

If you are having issues now at 10 mm, then jumping into something less would exasperate it. Return the 8 mm shoes and get some 10s until your achilles issues resolve. If you want to go less, pepper those in gradually. If you feel any badness, go back to 10.

Seems like a lot of work? It is. I did the same adventure, but am now back to 10 mm Nike vapor fly. I guess the born to run hype burned out for me.

Firstly interesting it is your PT making the call on 10mm? I have never run in 10mm shoes but I do generally run in Hoka. I had come from running in Altra before going to Hoka predominantly for the last few years but tried the new Altra Escalante zero drop the other day and my legs hurt more so after a harder run session having not run in zero drop for a while so I wouldn't be going straight there if I was you. I didn't like the shoe either personally. I like this website which you can compare drop amongst other traits of a shoe and may help in any decision making. Seems you just need to run in Vaporfly 4%...

http://fellrnr.com/wiki/Shoes

Yes. Of course YMMV, but since you asked for others' experiences... I switched from Asics Gel Kayanos to Altra Instincts many years ago. Not really any transition, I just bought a pair of Altras and started running in them. (I'm not necessarily recommending this strategy). I was probably running about 20 miles/week at the time, but it's been awhile so my memory may be faulty.

Prior to the switch, I was having a lot of problems with knee pain, especially when trying to increase volume. Since the switch, no knee problems. At the outset, like many folks, I definitely rediscovered my calf muscles, so a foam roller or trigger point might be helpful.

At this point I can't imagine not using a zero drop shoe - both for road and trail running. FWIW, I've found that Topo Athletic works better for me than Altra, so that's what I run in these days. The differences aren't great, though, and I wouldn't have a problem going back to Altra if I had to.

A couple of sayings “you always want what you can’t have” and “if it ain’t broke” I waffle between 10-12mm drop. This spring I started running in a couple different types of Hokas. The were great-stable, great feel- the rocker .... one of my favorite shoe plus all the cool kids run in them. Needless to say too many miles and a 5mm drop (before they were compressed) were the perfect combination for a horrible case of plantar fasciitis. They are probably amazing for others and they were great for me-until they weren’t . I should of known better.
For the record i’m generally leary of shoe recommendation from pts and chiros
Good luck !