For the snubber line itself, the objective is to get maximum stretch with minimum chafe. I have copied an idea from New England Ropes and created a line with very chafe resistant dyneema from the deck cleat to just beyond the bow roller, and then with stretchy dynamic rock climbing line from the bow roller to the soft shackle. Below is a picture of version #1. I am not sure how to put splices in the climbing line, so I have used knots for now (a figure 8 and a double sheet bend).
With this sort of solution, if I ever want more snubber length or more elasticity I could attach a piece of nylon from to the inboard end of the dyneema and take that nylon to a mid-ships cleat, and let our extra (about 20’ is available) until the dyneema is just still over the bow roller. I doubt that will be necessary but it is an available option.