In my experience it is not enough to use the gluestick, heatbed is really needed for such a large part. I just printed the XY part using Raptor PLA from MakerGeeks, on a glass covered with gluestick at 60C.
So while the bed was still hot after printing, I could not get the part from it. But when the bed cooled to the room temperature, the part separated on its own and I picked it up with zero force. This means that if the bed was cold, it would have probably popped off mid-print.
Now, PETG and such are another story. I printed T-glase and had to soak the glass bed in water to dissolve the glue and separate the printed part. Without water I broke off pieces of glass.