Oh no no no - the 1084 allows Max Overscan in NTSC and PAL, at least, mine did, so you can run 724x283 non-laced (724x566 laced) in PAL, and also 724 x whatever NTSC will go to (something over 240 lines).
You should also be able to run SuperHiRes for 1280-1448 horizontal resolution if you want, but things are a little more difficult to see (you have exceeded the actual resolution of the tube at that) and the Workbench becomes quite slow too. Interlace is still possible.
I liked 724x283 PAL, it worked very well.
Edit: that was with H-size and V-size set at minimum as well, and it was pin-sharp. I think the tube would be capable of around 800x600 resolution. Also, I had an early 1084S.