Most laminated wall TTs will have similar construction to your Jayco C. Some manufacturers do the job consistently better than others (Lance has devotees) and they are quite lightweight at any given size. Northwood (Nash and Arctic Fox brands) has a reputation for building traditional framed construction to a high quality, but are heavy for the size.
Possibly neither incorporates construction features you might equate with quality. Rear caps are pretty rare in TTs and fiberglass or aluminum roofs tend to come only with fiberglass or aluminum shell construction, rather than box construction.
My consideration for downsizing from my motorhome has me looking at unconventional TTs: molded fiberglass shell (Bigfoot, Oliver, Escape, Scamp, Casita) or aluminum shell (Airstream). This construction is more costly than assembling a box from flats, and for the size, priced sometimes much higher. Except for Airstream, there are no really large sizes. At Bigfoot, the largest shell is about the same space as a 28 foot C has behind the cab, everything else is smaller, some brands limited to 16-17 feet.
Queens or short queens are more typical of bed size, and some of the tiniest TTs you might not find actual queen dimensions in small molded shell trailers.
I suggest you look at Lance floorplans, most space for the weight. You may not find many Lance TTs used, the company is relatively new to the TT market and owners have been keeping them.
Tom Test
Itasca Spirit 29B
