Boys and Girls, lets get it clear, I'm not advocating getting rid of your bandsaw or scrollsaw, or even spruiking a jigsaw (let alone the Capex... though I may have hinted... hint, hint).
All I'm saying is that a jigsaw can do a lot of the jobs a bandsaw ('cept thickness) and scrollsay ('cept tight turns and minimal kerff), but then there are many things the jigsaw could do that the other two may not... at least as easily.
Basically what I may be hedging at is, if a novice (poor choice because of care required in the inverted position) asked whether he should buy a scroll saw or a bandsaw first, I'd suggest he consider a jigsaw... If you have both than a jigsaw could be an unnecessary luxury and if you didn't have a jigsaw, making this jig could be a tad futile.
If your first cut is too short... Take the second cut from the longer end... LBD