the solution for you depends, i guess, on how often you're doing this and what the workflow really is, but if a bit of manual intervention is okay, you have a ready-made solution: run command 1, change the tag on the resulting window, run command 2. acme just looks for an existing window with the expected tag to stick its output in, creating one if it doesn't exist. this also makes saving sessions really easy: change the tag to the filename you'd like it to have, type Put, execute. you can do that trick for 'win' windows for session saving, too. handy.
no info on your kill problem, sorry.
