It changes the pressure. The pressure on the boom is a function of sail area and wind speed and it has 2 primary vectors, horizontal and vertical. The boom acts as a lever which can multiply the force, particularly on the gooseneck which is at the end of the boom while reducing the pressure on the end of the boom. Mid-boom sheeting systems often have multiple attachment points on the boom, mine has 3, which serve to distribute the high loads found on mid-boom systems. End-boom systems typically have one attachment point, the question is how strong is the boom at the end section and how will the mainsheet be attached?
Regarding the Barton system, I see 2 issues with it. First I see little advantage to an end boom traveller that is only 28" long. The purpose of the traveller is to maintain downward pressure on the boom to increase tension on the sail's leech to control sail shape, at best, the traveller car can only move 12" from center(allowing for the width of the traveller car), which at the end of a 10' + boom is not very much, it will be somewhat useful going up wind, but again it is very limited. Off the wind there will be a lot of mainsheet hanging across the leeward cockpit seats and in a gybe a lot of mainsheet flying across the cockpit for people to avoid. This poses a safety hazard.
The other concern is the mounting system. There are 2 brackets which through bolt on the cockpit seat faces. Are the attachment points on your boat strong enough to withstand the pressure from the mainsheet, especially in the case of an accidental gybe?
Having sailed boats with end-boom and mid-boom sheeting, I prefer mid-boom. Getting the mainsheet out of the cockpit provides more room in the cockpit and allows for a dodger and Bimini. It is not as easy to trim the main from the helm when single handing, however, once the mainsheet is trimmed it is primarily adjusted with the traveller. I have long tails on the traveller control lines which reach the helm. This allows the traveller to be adjusted from the helm.