Can you tell us a little more about the conditions you were fishing in? I've used the rope lure before with good success as well. I was fishing relatively shallow clear water and sight casting to actively feeding fish though. I wish I had had one a few weeks back on Ray Roberts. That place has some monster long nose. I had a few bites, but of course they got off as I had a single hook streamer fly on.
Also, make sure you have some good pliers, gloves and a comb. They are virtually impossible to safely remove without those items.

Denton creek. It goes from walk across shallow to deeper than a kayak paddle. Very little vegetation. Submerged wood. Muddy brown water. Low visibility. Slow current.

I haven't seen the long nose gar feeding, but I have seen them rolling and swimming at and just under the surface.

Probably not a good location if the water is muddy brown for a rope lure. Just from my personal experience.
Live bluegill with a treble just under a bobber would be what I would try there.

Definitely do not need a minnow. They are attracted to the pulsating movement of the rope hairs. Minnow scent is good though. So is blood, shad, etc.

We catch them with no minnow or bait. Just nylon rope. I will try to get better pics next time.

How far under the bobber and where do you like to hook bluegill to keep them alive the longest?

About 2/3 of the way back and about 2/3 of the way up from the bottom.

Depth will vary, but I would guess they are usually in the top 50% of the water and most
rivers aren't that deep. 2- 6ft I would guess.