It is important to note that the PECO Tools PT30 is specially formulated to be applied to dry ballast, and requires a particular technique for application to ensure successful results.
Once the track has been laid, the ballast is firmed around the sleepers, ensuring that it neatly settles in and does not interfere with any moving parts. Once the desired effect has been achieved the modeller then applies the glue, using a glue applicator such as a pipette or syringe, along the centre line of the track, between the rails. Further applications of the glue are then made outside of the rails, and along the shoulder, but in all instances what you don't need to do is to saturate the track and ballast, as is often the case with other types of glue.  It's more of a case of "Precision Gluing"! It is a thicker glue than the watered-down PVA often used, so will first sit on top of the ballast. But over time it will disperse within the ballast particles and reach outwards towards the ballast shoulder. After a minimum period of 24 hours the glue will have dried and hardened, fixing the ballast firmly in place, although it is possible that some small areas may need further glue application where necessary. 
The attraction of this glue is that it is ready-made, not needing to be mixed, watered-down, or have additional additives put in such as washing up liquid. It comes in a convenient and handy 500ml bottle with a screw top, supplied in singles and available now from stock.