There is no trick I know of, however my best advice to you is to goto Attohwa Chasm for your upgrades to Colorful. Since Colorful can be obtained in any zone, I find this area the easiest. The T1 is possible to 1 shot if you have enough brute force, it only pops at Fluxes 4 and 8, very easy to track and kill once you get the hang of it, and I have good experience with it upgrading quickly. This is the same way I did the 75 Souls for my Ochain, however so far as I know, there is no way to make it less annoying, the VNM system is by design very annoying, but so long as you have to do it, this is my best advice so far as getting your Colorfuls.