Vertical end lines?

Is there a way to make the End Cap of line with a Solid Line Body the same thickness as the body when thick or thicker is selected?

Similar to the way to make the end line of trills bigger.

On that note: Is there a way to have the end cap for trill lines turned on as a default, so as not to change on individual basis?

There’s no engraving option for trills to always show stop lines, though it’s not unreasonable to request that, so I’ll make a note of it and we’ll try to implement it soon-ish.

You can’t currently design your own line types, but you will be able to in a future version when a complete line editor is added.