That is very good money spent @osirissailing! If you cannot get LMR600 you can use RG-213 cable - has a very small loss. Make sure you get the best compression termination connectors you can afford.
VHF is line of sight, so for a 40' boat with standard average mast heights, your maximum range should be in the order of 40-50nm. You can work this out if you have the height of the aerial above the sea surface and what dB value your aerial is (6 or 9d
Basic safe ranges:
Sailboat to shore: 35-50nm (higher shore mast)
Sailboat to sailboat: 15-20nm
As they say, the best liferaft is the one on top of the mast.