I am running character generation per the rules in Mongoose Traveller, with High Guard and Mercenary with the following exceptions.
UPP Generation: Roll 12D6, and re-roll any 1's that turn up. Any 1's that are re rolled are kept. Assign 2D6 pairs freely to each characteristic, keeping in mind the intended role of the character.
High Guard ranks: I find 9 enlisted ranks too many to go through and have a reasonable character for the job when only rolling every four years for advancement. Promotion, on the first term only, is to E-3 on the table (Able Spacehand). Interestingly, this is more consistent with the basic Mongoose Traveller book. When rolling for commission in a specific Naval Career, enlisted personnel with a minimum grade of E-6 will stay in that career, and are promoted to O-2 (Sublieutenant) before the end of the term.