If you are re-equiping sailing club safety boats then in my mind octaplait for anything other than the anchor line is luxuray.
For the bridal use normal 3 strand nylon of a reasonable size, reason is as the carabina slides over the tow line it knicks and abrades. If you put carabinas on each end its very useful for other jobs like a foot step to get in when cliped to the lifelines and hence can disapear. I used to shackle one end to the transom to stop it walking, but then you must drill the users not to drop it - carabina & nice prop -
Also if you need to bin the tow in an emergency its the bridle that gets the knife.
Tow line - minimum of 10 to 15m last thing you want is the casuality surfing down one of your stern wave and into the engine cover - it gets expensive if its just the cover, really anoying if they get your spark plugs!!
A Carabina on one end of the tow line is useful, a so it can slide on the bridal ( opps wrong version got that stuff on brain) and b so if you are total inversion recovery or lee shore its a lot easier to reach under a clip onto shroud, fore stay etc than bugger around tieing knots.
I would also not use octiplait for this, though its idea for the shock loading. I 'm yet to meet a safety boat drive how has not a some time power winched the tow line ( collected the tow line round the prop) and then momentarly wondered why its gone quiet followed expletive delitive. The club I used to be at used soft ploy prop and hoped it lasted 2-3 seasons before some one destroyed it.
I would also recomend issuing 2 tow lines as if it bets hairy you might need ot bin one line or pass the tow line to another boat .
A couple of coastal clubs have put small hand buoys on the end, to float the end to people, ( also if your good it aids the trowing of the line to get some good acuracy - opps sorry was that your head!!)
For the anchor line put a hand bouy on the bitter end incase they have to leave the anchor some were in a hurry or get it snagged.
A good Idea I saw at one club was fitting samson posts on the safety boats even though they were 4.5m Tornados & Seariders. This made life alot safer not having to lean over the back of the boat to adjust the tow and you could work solo easily if needed.
When you are specing a safety boats anchor remember there can often be a load a dinghies hanging off you thus increasing your loading. But don't make it so big you fall over it and damage the crew when they are working. - Granny and Eggs I guess