Time for a new towline; I've chosen the North Water Dynamic Pro especially for its low profile when packed. The North Water can be worn at the front (attached loosely) to help rolling as I usually surface over the back deck. However, I've made some significant changes to improve the product (IMHO). Note the carabiner clipped into a holding ring ready for deployment.

Unpacked

1. Rather than being being a fixed shape bag or box, the towline container is a pouch that unravels.
2. The connection between the 'tow-er' (person doing the towing) and the 'tow-ee' (person being towed) can be likened to the connection between a car and the road, ie the suspension. Do you want a 'bone shaking' or a 'comfort' ride ? I've replaced the NW shockcord loops (only about 20cm long - very little 'give') by a metre of 8mm shockcord. This gives a far more forgiving towing experience to minimise the chances of injury to the 'tow-er'. One can attach the line and paddle off at speed with no worries of a sudden jolt and likewise in big seas towing when the line is likely to pull tight suddenly.
3. The shockcord is attached by a fisherman's knot to a short piece of cord then to a 'D' ring to provide a clean pull on the NW webbing.
4. The main towline is attached to the shockcord by a fisherman's knot.
5. The line is shortened by daisy chaining with a quick release to give an overall length of about 6 metres. At full length the towline is about 15 metres.
6. The quick release knot for the 'tow-ee' (Simple Simon Over with drawloop).
7. The carabiner.

The carabiner is plastic so there is no need for a float as it'll only sink by centimetres. If the 'tow-ee' wishes to free the towline, the 'tow-er' needs to stop paddling and the 'tow-ee' can overtake the line to reach the quick release.

For fast repacking pull the line in quickly, looping it over your arm...

... fit into the unravelled pouch, roll the pouch up and fasten with the velcro.