The only things I would say are firstly, that if your head expects there to be a bypass, use it, or you may get uneven cooling resulting in poor running and damage, and secondly, NEVER USE ANY BODGER'S ACCESSORY, which includes such awful things as oversills, but in this case means a convoluted bypass hose. What you want is a short length of heater hose and two nice, new Jubilee clips, preferably stainless. It will last for many years. Remove the water pump to be able to fit it (unless you are having the head off, which is not that hard), and use a new water pump gasket afterwards.
In an emergency, if the bypass hose fails, you can just shorten one of the heater hoses (there is usually plenty of length) to get the material to make a new temporary bypass hose. The last one i did that way became permanent, as it lasted for years, and maybe 70k miles.