It sounds to me like you are a small-framed person, and the 243 is unwieldy for you. The Marlin is a probably a shorter gun and therefore you feel more steady with it.
Will you be walking, stillhunting or driving deer, or will you be primarily stand hunting? The weight of the gun won't matter much on a stand, and a good rest will take care of the wobbles. Do you plan on shooting longer ranges (beyond say 175-200 yds) where the 243 would be best suited? If you're not primarily a stand hunter and don't need to shoot too far, I'd go with the lever and put a low power fixed or variable, wide angle scope, or even a peep sight on it.
A 35 Rem is a great deer gun. The Marlin lever will have some kick but it is not too bad. Go ahead and shoot it and if it suits your needs better by all means use it.