I only have experience of PVC Zodiac repairs, although the preparation is roughly the same.
for a detailed Hypalon step-by-step guide.
I think this will be a fairly major undertaking, however, given age of your boat, it doesn't have to be the tidiest job in the world, as long as it gives you a new rubbing strake to protect your tubes. Later Zodiacs (mid 80s) - also incorporated a ridged edge on the strake to reduce spray.
The rubbing strake may need to be applied in sections - partly bacause of the overall length of the strake and the fact you need to work quickly within a set time-frame for coating sections, etc. Either that or work with a friend.
You'll also need to work out if you repair this when the boat is inlated or deflated? Inflated - means you should get less distortion applying strake, however deflated has advantages in allowing you to apply an even pressure onto the rubbing strake to make a secure bond. Good luck!