I don't make minnow rigs ... but I do make jig/leader rigs. (I "push" jigs)

12-18" of 6lb test mono is what I use, since my main lines are 10-30lb test.

My trolling weight (barrel sinker) is on the main line and a duolock snap is tied on the end ... so the leader line & jig are sacrificial if I get hung up too bad to get loose. The leader has a loop knot on the other end, and that slips into the duolock snap ... quick & easy change out.

I determine line poundage to use based on the heavier pound test of my main line ... so that just the jig is lost.

I use several different brands of line for my leaders. Just use brand names and you'll be OK.

Yes, it is fairly typical to add the "setups" to your line, once you get on the water ... and it's certainly a lot easier, smarter, and safer than going thru the hassle of trying to wind them around your rods for travel or storage ... especially when you're talking about double rigs !!

You could probably do with a "pool noodle" ... cut it in sections & use it to wrap your rigs around. A lot less hassle than putting them in a ziplock bag and having to untangle them when you get them out.