Just to through my two cents into the mix, I got a Gemini lead kit last year seen below.
While I agree 100% that they are very easy to make and the fact that you can alter the size of the mould to make 4-7oz makes it a very attractive option. However I found some major flaws in the leads themselves as well as the kit.
Firstly the assortment of gear you get limits the amount of leads you can make with only a few of the wires that go into the middle of the weight included. You did very well by the way getting the extra gear from them for that price. It can be pricey buying the screw on tops for the leads afterwards. I've paid €9 for a ten pack.
Also I found that the wire that goes into the middle of the weight, where you'd clip on your rig to is very long and tends to bend very easily. Not a big deal as it will bend back but it's just another job between casts. A big problem though is the griper wires on the leads. Sand, muck, grit etc gets into the groves very easily on retrieving your gear. The wire will not click back into place when this happens, and it happens often! I found myself cleaning out the grooves with a bait needle all the time to clip the wires back into place. And as there are four independent wires on each lead you can have to do it four times. On top of bending the wire back straight this becomes a real hassle you don't need.
Lastly I found that casting these leads much harder then the normal bullet shaped Breakaway style. Very often the lead goes into a spiral or a wobble during the cast and then spins the trace around in flight. This definitely has cost me distance during casting and some very mixed up snoods.
All in all I have decided not to make any more leads with the kit as they have proven too time consuming while fishing unlike normal leads which give no trouble at all and are easily managed in comparison.