minimum amount of trim to make bubble hash?

Should be plenty.  I bet you yield around 3 grams at least.

 

I'm digging that tray man! Looks nice. 

 

 
I use about 1/2 of a gallon ziplock bag. Not entirely sure but it's generally about 4 ounces of trim. This post should help you a bit...
 
http://forum.grasscity.com/harvesting-processing-medical-marijuana/1340470-how-make-full-melt-ice-water-extract-tutorial.html

 

yeah I would try and do a qp at least, probably wont yield much unless its super fire trim

 

My super fir trim will produce about 3-5 grams dabable material.  But it is crazy fire trim.  Returns over 20% on solvent extracts.  But 30 grams is the minimum I will run.  Check out Brother Urb's tutorial.  How to make full melt ice wax.

 

Just keep in mind you genrally will get back 10% kief. So you need 10 grams of flower for 1 gram hash

 

i like how the last post is from today how ironic