I used this castable refractory cement from amazon a while back....
https://www.amazon.ca/Rutland-Castable-Refractory-Cement-12-5-Pound/dp/B000H5T5EA
I applied it on top of the K-wool and then I used the ITC100 on top of that. Made a good liner. I procured my ITC100 from Princess auto as well. They recommend spraying it...... I tried and nearly destroyed a wagner paint sprayer (they ask for a stippling sprayer). I ended up brushing the ITC100 on.
I has a second project that needed a liner and for that I forwent the cement and just used standard refractory + ITC100. I find the cements are not economical by volume....