Thanks for asking about this in the forum.
I will try to keep my answer brief but do my best to explain things.
It is always going to be a bit more involved with boundary signs, because you have a lot of freedom to step away from normal rules. Colours, sizes, shapes and fonts can all be varied in 2401, 2402.1 and 2403.1.
2402.1: This sign has two versions. The simple 'one line' place name is just created in the exact same way as a non-primary sign. With the second one that has different sized text, it is important to consider which text is the normal 8sw high text, which text has been scaled up and if any text is scaled down. Looking closely at the working drawing it is clear the 'Welcome to' is the normal sized letters. It is this 'Welcome to' that remains 8sw high and the border size is related to this. The AXTLEY has been scaled up. The detail block x height must also be entered based on the normal sized 8sw text, not the AXTLEY text.
2403.1: The sign has an additional bulge at the top. Currently in KeySIGN the bulge must be added manually, using AutoCAD commands to draw, offset and trim the sign border. You would start by creating the sign without the bulge in a similar way to 2042.1 then explode the sign borders so that they can be trimmed and filleted together with any bulge added. We already have a 'wishlist' item to create 2403.1 sign in a quicker way, which Keysoft intends to develop in the near future.
Hope this helps to explain things, but feel free to email support if you require more detailed help.