The problems with printing grid based bootstrap html pages using phantom-pdf recipe are usually caused by it's responsiveness. The recipe is using a fixed screen size during printing (currently 600x600) to which bootstrap reshapes the page. This is usually unwanted and makes the printed pdf look very much different than the original html. Another problem is that recipe applies bootstrap @media type styles during printing which also makes sometimes quite unexpected results in pdf.
One think I can do here in jsreport is to make the values of the screen size configurable. This should make using responsive css easier. Although I am not sure if using such a complex responsive library makes sense for fixed sized pdf files.
I have tried proposed workaround on my own and it works for some limited usage, maybe you will be lucky.