You could do what iTerm2 does. If a new session is opened in a new tab, ignore the configured window size and use the one from the existing tab(s), if opening in a new window use the configured window size. Best of both worlds!
Another suggestion in the shell menu it would be great to have additional New Tab and New Window options with an arrow which goes to a list of the configured hosts so that you can open a new session to a specific host directly from the menu rather than have to open a new tab / window with the host list and then open a specific host. Much easier and less clicks.