Well, I own a Bell Morningstar and it would be a sweet boat when you’re paddling TANDEM. I solo mine, but am more than twice your weight and 6’1" with long arms and torso. I think a Morningstar or Prospector will be much too wide for you to enjoyably paddle solo?
The Starfire, now made by Colden, is a better bet. Sold mine to a friend and he and his wife tandem in it (I soloed it all except one time). Problem is, finding even a USED Colden, Bell, or Placid (all 3 companies made this hull) for less than $1000 will be darn near impossible.
A better bet may be something like a Mad River Malecite. Not as maneuverable as the Starfire, but much better than the Solo Plus. Also not as “Twitchy” and more predictable than the Solo Plus. And MUCH easier to find on the “Used” market.
Another would be the Bell Northstar/ Northstar Polaris. THe Polaris is a really nice tripping boat for smaller paddlers. It can be soloed and also a much better option than a Morningstar, albeit a bit large for a 120lb paddler solo, as all tandems will be. One thing I didn’t like about the Northstar is the differential rocker. Having loved the Starfire, I figured it would paddle like a larger version; it didn’t. It will maneuver just fine, but the Starfire “Spoiled” me!
If you want a royalex hull, look at something like a Dagger Reflection 15 or 16. It will be more difficult to solo than the Starfire and the Malecite, but nice for a royalex boat.
All that said, a solo AND a tandem would be a better bet. You or someone mentioned a Flashfire? If I was YOUR size I would never ever have sold mine. I enjoyed it paddling around our pond, but I was much too big. But what a playful, fun little boat! And my wife paddled hers for several years on the river and never swam after her first paddle, where she hit a strainer. If only I had quit growing when I was in my teens (LOL)!
Good luck, and you really need to try these boats if you can!