This is because you're considering the wrong regulations. Operational regulations are irrelevant. What you need to consider are certification regulations. A two engine transport category airplane, be it a Lear 60 or a B737, must still meet the same performance standards and design criteria with respect to minimum gauranteed performance, and they're still flown the same...especially with respect to takeoff and landing. Transport category aircraft are transport category aircraft, big or small.
Right, certification wise there is no difference if both are certified to the same regulation. However there are still different operational regulations and those govern performance calculations as well. In fact the safety margins imposed on airline operation are much higher than on non AOC operation, especially for performance calculations. And therefore they do matter if the question is to what regulation you operate an aircraft, which was exactly the question asked by Ashling.
Of course you are right, V1 is V1, and aborting after V1 is not teached in either case.