As a rule, I generally post stuff that is either A) probably going to appeal to someone else on the forum somewhere or B) which I think folks should be interested in, they just dont know it yet. Perhaps if more people knew who Cassar is, or who Sarpedon is, or for that matter what a bigature is, it may be worth posting.
Regardless, I have been playing about with my new liquid green stuff in an effort to figure it out. Luckily for me, Ikeda-san sold me an IG Manticore which handily had a couple of small gaps to fill. Yay for commerce!
Here is the section of one of the Manticore's big nasty rockets. (24"-120", S10, AP4, Ordnance, Barrage - D3, Large Blast)
Two of the rockets had this problem, so I did them both with LGS.
On one of the rockets, I just applied it neat as M_i_J suggested. LGS has the consistency of Marmite (Vegemite to those of you from down under, or very gooey Peanut Butter from those of you with a more American upbringing). On the other, I first mixed a teeny tiny drop of water in with the LGS to give it more of a foundation paint consistency.
Here are the results.

The top one is undiluted, the bottom is with the water. Bearing in mind that this is my first time to use this stuff of course.
The neat LGS dried with quite a rough finish, the water/LGS mix came out a lot smoother. It dries about as quickly as paint and after 2 thin coats on each, both sections look a bit better and are ready for painting. I would definitely recommend adding a little water (just a tiny drop) to the LGS, and doing 2 or 3 thin coats on smaller gaps. On a bigger gap, you can do the first layer with pure LGS and the second coat with water to smooth it out a bit.
Or you can pour baking powder all over your room.

Painted Minis in 2014: 510, in 2015: 300, in 2016 :369, in 2019: 417, in 2020: 450