Thanks The WelshPirate
and welcome to the board!
Interesting thoughts... I like the idea of the Hecla having a less than glamourous, work-horse type, role. Would the smaller nacelles really effect speed? I guess it's all depends on how you reckon warp drive works. Perhaps, larger or more numerous reactors would overcome the disadvantage of the shorter nacelles, allowing the ship the power to reach high speeds, but not maintain them for as long. With a role keeping her in or close to Federation space, with short mission durations, this wouldn't be much of a disadvantage.
Anyway, good luck with the 3D-ing. Blender's a good package, just try not to be too intimidated by the interface.