Flying Dragon is dwarfing, in part because it is slower growing than normal Poncirus.
Flying Dragon has a longer winter dormancy period, and that will be transferred to the grafted scion to some extent.
The winter dormancy also depends on your climate, and any extra heat or protection you give the plant over winter to bring on spring.
To answer your question in reverse,
If you grafted Myer Lemon on a more vigorous non dormant rootstock, the combination would grow faster than Myer on Flying Dragon.
I've had a Washingtonia navel for many years and I forget what rootstock it's on but "Flying Dragon" sounds awfully familiar and I think that's what it is. Not sure.. At any rate, I ordered Flying dragon seeds to try and grow rootstocks for grafts from my orange tree. I have some questions..
It should be possible to tell what rootstock the Washington is on from pictures of the trunk at soil level to just above graft union. Any suckers will make it much easier.
As you think the Washington is on FD, how large is that tree and how fast or slow growing is it ?