After firing each loose end with a torch, or over my gas stove top, I used to press the near liquid end flat with a wet knife or putty knife edge...
You have anough plice strands there that is will never pull thru anyway....three used to be standard for manilla, I usually did five with more slippery nylon....
that spreads it out like a mushroom cap and prevents it from pulling thru the splice...The is also "rope dip" available which probably is much like liquird electrical tape.....you can also whip/ seize.... the end tight with waxed nylon....wrapping it tight .....probably still available at marine stores....