First off, your particular body geometry is going to play a role in sizing. Specifically, how long your torso is. 5'2" and all leg is different than short-legs and long torso.
A recent Small-plate discussion:
Small BackplateSmall Backplate
If you are going to go with a hard-plate and harness, maybe you will need a "small" plate or not, but some plates like the Halcyon that Marie13 showed, require an additional Singe Tank Adapter (STA) to attach the cambands. More bulk and travel weight. Others have cam-band slots built in.
If you are staying single tank there a couple single-tank specific plates that are lighter and less bulky for travel:
Golem Gear - built in stabilization:
Golem Stream Backplate
View attachment 525036
Freedom Plate - also available in small size, AL or SS:
The new Freedom Contour - The Rolex of backplates.
Freedom Plate Divers Roll Call: show us your rig!
Freedom Plate information bulletin: Please read
Freedom Plate information bulletin: Please read
You also can use the same harness assembly on various "soft-plates" from OxyCheq, Apeks, and others for less travel weight and bulk.
Going this route, you have more options and configurability, at the cost of doing more work of research, purchasing, and setup.
Soft-pack assemblies like the OMS IQs, Dive-Rite TransPacks, and HOG Total Buoyancy Control systems give you a finished solution or all of the parts (that are known to work together), with varying degrees of customization.
If I was buying just one wing now, for your range of uses, I would probably choose the Vintage Double Hose 35# for maximum flexibility - the VDHs are so compact in width that there seems to be little streamlining penalty for up-sizing.
FWIW: I have just moved from an old OMS IQ (regular) to a standard-size, but extra-thin (material - not cut) stainless Freedom Contour plate, a customized/converted harness derived from surplus Dive-Rite TransPack/TransPlate parts, and a HOG 32# wing.