In reply to Burly1973:
Mera Peak, I used approach shoes to Khare and Sportiva G2’s to Mera La, high camp and summit.
On Ama Dablam, as Ken says it can vary and I’ve been to Camp 2, in dry conditions, in approach shoes. Last year the SW ridge was in prime condition, and I opted for G2’s from Camp 1 onwards.
Some things to bear in mind, ensure you’ve got some toe wriggle room in your high altitude boots. Mera might be straightforward but it can be chilly. Autumn on Ama Dablam gets progressively colder and December summit days can dip to -20 C. Pre-expedition footwork training in your big boots will help you enjoy the great granite climbing between Camp 1 and Camp 2. Consider switching to big boots a day before you need them, so as to get used to them.
They are both amazing mountains.