I like starch far better than flour/water.  The liquid starch is just fine.  Try some samples to see if the results you want are best when you use it straight, or thinned down a bit.  Cracking with some adhesives is often due to the thickness of it.  In most cases, more adhesive is NOT an advantage.

I'm not sure about longevity, but I can't see it being a problem, personally.

Also, starch doesn't attract vermin. 

Sue