The tactics of the Rebellion are built more on speed than the perfidious Nelson. The Rebellion did not have the level of ship building nor material advantage to fight a large and lumbering opponent. I would argue that their tactics are more based off of the Danes fTom The Gunboat War rather than Nelson.

What is going on

The Ackbar Slash has been disputed by some as a post-hoc description of the tactics utilized at the Battle of Endor.

To understand why this might be the case, we should first examine the order of battle at Endor.

In his Treatise on Intergalactic Warfare and Tactics, Admiral Ackbar boasts his vehement support of the doctrine in which the collective firepower of the allied fleet would focuses their weapons on a specific, single target of importance. He further illustrates that in realizing that they had been lured into a trap and surrounded by the forces of the Empire, he turned to the advice of one of his subordinates, one Lando Calrisisan of Corlellia.

Being of Corellia, Lando's experience with the Naval Academy there had impressed upon him the importance of maneuvering to the enemy's disadvantage. In New Republic, Calrissian is quoted as having stated that when confronted with a superior force, it would generally be a superior alternative to place your own forces as close to the enemy as possible, in an attempt to disrupt the enemy's movement and ability to simply trade ship-for-ship using their superior numbers to win the day (in a worst-case scenario, for the larger force).

I think perhaps we give too much credit to Ackbar and not enough to Calrissian, but the facts are that when combining Ackbar's strategy of concentrated firepower and Calrissian's strategy to close as close as possible, the Empire simply lacked the ability to respond adequately to the Rebel Fleet's rapid advance, underestimating their discipline in close-quarters as well (Warfare and Tactics 66).

As we saw later in Nelson's maneuver at Trafalgar, Nelson had actually slightly modified his earlier tactic from the Battle of the Nile (coined, "crossing the T") in favor of splitting his force into two lines, and running them through the French battle lines instead. In Nelson's case, this was in part due to the large number of assembled ships, and the weather gauge being against him. He had to approach the enemy whilst taking fire from the French broadsides while unable to return fire himself until his fleet had closed the distance and passed through the French lines.

This maneuver actually more closely resembles Calrissian's tactical suggestion at Endor than it does Ackbar's. That's not to dismiss Ackbar however, as the concentration of firepower was often key in the age of sail to whether down ships rapidly by focusing their fire on them one at a time, rather than spread their canon-shot amongst multiple ships (where possible).

I suppose with any question of this nature the "exact extent" is a subjective judgement, but it remains apparent that Nelson's tactics were influenced by the Rebel Fleet's actions at the Battle of Endor. Whether that is more attributable to Ackbar, Calrissian, or both (my opinion), is up to you.