Bigger as in you want more drop or bigger as in more cushioning? I'd venture the heel cushioning isn't causing achilles pain (especially if you're already on Hokas), on the up if you have an inconsistent strike I think you're probably loading your forefoot more and putting more strain on your achilles. You may also have an inconsistent stride not just foot strike. I dunno, I'm an amateur at this stuff. I was born without cartilage in my sub-talar joints in both feet and up into my early 20's, until I figured out what was going on, I literally couldn't run more than a mile without unbearable pain (I was over-striding and heel striking). I had to reteach myself how to run and totally change everything I did, and I've been tweaking it ever since. I think fellrnr knows what he's talking about and if you're overstriding or not averaging around 180 strides per minute I'd start there. So much can be cured with proper cadence. However, achilles issues, in my experience, are more tied to going too far and too long on the forefoot. It especially sounds like this because you refer to your left leg having "suspension", that feeling comes with a solid forefoot strike, if you can get back on your midfoot or even slight heel you won't be loading your achilles and lower calf the same way.
edit: To add, especially because you aren't getting that feeling on the down, you're transitioning more to a mid-heel on the down naturally and therefore your achilles isn't getting all of that force any longer. Consciously change your strike going up and see if it makes a difference.