The initial fluff requires the federation to become much looser as we head away from the core worlds. By the time we are at the frontier the worlds have a lot more local autonomy but receive regular cultural updates from the trade lanes - think about how the US spread US culture across the 'wild west' or how the British Empire spread its cultural values despite months of travel time.
The travel times issue begins to skirt the question of whether we want to think in terms of a B2-only "small-ship" setting, or a HG2-compatible "large-ship" setting.
B2-only ships would let us have J-5 couriers at TL11 (below the very top of MolaFed tech), allowing for a perhaps 20-parsec-or-less-wide polity that could be traversed fringe-edge to fringe-edge in a month in an emergency, with reasonably-sized J-3ish couriers to haul diplomats and Mail around the 10-to-12-parsec-wide central core in the same time frame. I reckon this mechanic would give the desired control model, graduating from Kinda High to Tenuous the farther out from Molador one Travels.
On the other hand, if we think in terms of HG2, we are looking at hard limit of J-3 for the MolaFed (as per LBB5), with clients and rivals pretty much stuck down at J-1, but with occasional J-2 vessels. It would also give the Federation Navy a
significant advantage over its likely opponents in terms of firepower and defensive capabilities. (And make options for in-space PC shenanigans more limited as a result.)
Given that we already have a well-developed HG2 sandbox provided to us in the Islands Clusters Campaign from TCS, I am inclined to favor a small-ship model here, because the closer parity in capabilities will make throwing its weight around much more difficult for the Federation Navy in particular, and for the Federation Government in general. Thoughts, anyone?
Also, with no Xboat net, as we map the sector out, we will want to mindfully consider and deliberately build the structure of the web of Trade Lanes and Mail routes with an eye toward how they might facilitate or hinder the flow of culture to particular individual worlds, as read in the LBB0 source.