Assuming the usual massless pulleys and string, the tensions are all equal. When horizontal, the effective force at 4ft is T + T/sqrt(2), not 2T, because the string joining the two pulleys is at a 45 degree angle, so then the mechanical advantage is (6+2sqrt(2)):1, or about 8.8:1, assuming the lower pulley is at floor level. If the bottom pulley is 6 inches off the ground, the advantage drops to 8.4:1.
Do you want it for all angles of the press? The string between the attachment point at two feet and the bottom pulley will rub as the angle increases.