Ideal Gels for Gen 9

So I’m sorta new to the whole gel blaster stuff and I’m quite confused between the differences of gels. I’ve heard some are harder or more consistent. Would someone be able to explain the differences between them. I have JM gen 9 that’s currently stock, what would be the optimal gels for it? Cheers.

If its stock plastic barrel. Give the orange or hardened heavier war interest gels a shot. At 7.3 to 7.5mm they would be ur best bet.
If u had chucked a bruismaster tight bore in 7.0 to 7.2mm barrel in then gold pack milkies would be ur gel of choice.