Costco USA Car Hire Insurance Cover

[DisneyArab]

I have booked car hire through USA Costco site which is much cheaper than UK. However, I am unsure on the insurance cover and would like some advice.

I have booked a minivan for 15 days for £784 for Florida next July. However, the Alamo car hire only includes the basic insurance cover. To add Collision Damage Waiver and the Supplemental Liability would by $45 per day extra on the rental (circa £500 extra).

Having looked at Martin Lewis' website (Money Saving Expert) there are companies that offer car vehicle hire insurance and there is a comparison site (moneymaxim.co.uk).

A worlwide insurance policy (annual) would cost approx. £84 and inlcude:
- £7500 excess cover per incident
- £100k CDW
- $1m SLI
- 7 named drivers

Has anyone done this before and have any advice?