You are one of a set of triplets and are engaged in a dark, Battletechy game to determine who will succeed to the throne of your world. Planetary law typically grants the title to the firstborn unless they are removed by the lord or The Council of Chivalry, but a special law exists for multiple birth situations where ten years of Mechwarrior military service under conditions designed by the Council of Chivalry will lead said council to a decision on who will ascend to the throne. You and your siblings have passed through many trials, finally passing through your academies and their related officer training programs summa ****** laude just to be presented with the final test. You are to serve those years in a 40 tonner of your choice serving the state (It does not matter which you want it to be for). Your performance and acts will be evaluated by The Council who will make the final decision on the basis of your career and choices during your military service. Choosing a mech will play a role in what type of company you may be assigned to in your initial regiment and greater career.
You can assume that there will be intrigue including assassination attempts and accidents as there have been throughout your entire life. If a sibling is traced to them, they will be removed from the line. You will be judged in part in a way that handicaps your choice, but also that values a good starting choice. This will technically take place in the 29th century, but mech choices will be allowed to be anachronistic to add to the scenario. All pretenders will also be assigned tutors during this service who will prepare you for the throne, but who may also remove you and who will be sending regular updates on your progress to The Council. What mech will you choose?
When you make your choice, you will in-character justify it to the council. This will be part of their screening process to determine if you made a better choice, but they are not daft and will easily identify an objectively poor choice.
Assume that The Council is biased against you from the start; you have a steeper hill to climb.