The best designed Lehigh guns (generally the earliest) have relatively little drop at the butt, and are fairly "straight", despite the visual curvature. Ok, the straight, level wrist takes getting used to, but otherwise handle well! Many later Lehigh guns (like so many later guns from everywhere else) have way too much drop in the butt, accentuated by the curves, and I would not even care to try to shoot one! I wouldn't be able to see the sights anyway with such a ridiculous amount of drop, no matter what caliber.
The cheek area should be relatively level and straight and in normal position, with any curve being behind (curving down to the buttplate), and ahead (curving down to the nose of the comb). It should not "hump up" towards your face (though I have seen old guns that do... ugh!). Basically, your face should not be able to tell that the comb is curved.
This gun I did has much more drop in the butt than guns I normally do, but I managed to make it work out well, and it handles and points and shoots very nicely. Notice that there's really not all that much curve in the comb anyway. And it's a .54 caliber rifle, so it's not a little squirrel gun! It takes VERY careful cheekpiece shaping (all guns do... I am a cheekpiece fanatic!) to get it all to work right, but it can be done.