So I need to stretch an afterburner trail, because the effect I just GIMPed and hacked into FS:

looks like crap.
(IGNORE the empty alpha channels and the fact that I haven't replaced one of the afterburner effects- I haven't corrected those yet).
Is there any way to stretch out the effect so it doesn't look like vertically-compressed crap?
I CAN'T do it via: ships.tbl, where the trail is specified, the image itself (resolution and aspect ratio)- 256x1024 is rendered the exact same way as 128x4096 (those resolutions are not final, don't worry), or apparently any other table.
Is there any way to change how long the effect is, and if not, how easy/impossible would that be to put into FSO?