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The source models an ideal journey with constant proper acceleration of one g. Accelerate to halfway, then reverse acceleration and arrive at rest. For a one light year target, the source predicts about one point eight nine two ship years and two point two zero eight Earth years. Both curves use years on the same fixed axis. These are separate journey totals, not an animated clock or an engineering mission design. Increase target distance from one to four point two four light years while keeping one g and halfway turnover fixed. The source calculates rapidity from inverse hyperbolic cosine of one plus acceleration times half the distance divided by c squared. Ship time is twice c over acceleration times this rapidity. Earth time uses hyperbolic sine instead. Both markers follow those actual source expressions. At four point two four light years, ship time is about three point five four zero years and Earth time about five point eight six six years. The Earth time exceeds ship proper time. The ideal model ignores fuel supply limits, acceleration hardware, interstellar hazards and realistic navigation. The comparison is grounded in the page’s actual constant proper acceleration equations. Keep the same one g halfway-turnover model. At a one light year target, peak speed is about zero point seven five one six times light speed. Peak occurs at the turnaround, not at arrival. In this itinerary the ship brakes back to rest. The vertical axis is speed divided by c, with one representing light speed. Increase target distance from one to four point two four light years. The source peak speed fraction is hyperbolic tangent of the half-journey rapidity. The marker rises toward one, while remaining below it. This parameter sweep compares different journeys; it does not claim the changing target distance represents position along a single flight or a physical time scale. At four point two four light years the peak speed fraction is about zero point nine four nine five. The speed remains below light speed and arrival speed is zero after ideal symmetric braking. This is the source trajectory calculation before display formatting, not a guarantee that a spacecraft can sustain one g or carry the required propellant. Now fix distance at four point two four light years, one g, and halfway braking. The total rapidity is twice the half-journey value. The ideal carried-fuel mass ratio is exponential of total rapidity divided by exhaust speed fraction. At exhaust fraction zero point nine nine nine, the mass ratio is about thirty eight point seven eight. This excludes a real vehicle system design. Reduce exhaust speed fraction from zero point nine nine nine to zero point five. The total journey rapidity remains fixed. Dividing by the smaller exhaust fraction increases the exponential, so the mass-ratio marker rises sharply. The graph has fixed linear axes. This change affects the source ideal propellant ratio, while leaving journey time and peak speed unchanged. At exhaust speed one half of c, the ideal mass ratio is about one thousand four hundred ninety three. This compares total initial mass to final mass within the source rocket expression. The source externally powered lightsail option sets carried-fuel ratio to one, but that does not imply the beam, sail or whole propulsion system has no mass or energy cost. No feasibility claim follows from these curves.