From what you've posted it sounds like the NWCOA insurance program is the best deal for you. I've never had that policy, but make sure you know if there are additional costs for adding temporary help and if so, what the cost is along with if there are any costs for additional insured or certificates of insurance and if there is coverage for uninsured subcontractors. I know that with the NWCOA program there used to be the fee for the business owner plus one individual, another fee(s) for additional employees, and a fee for occasional help that was good for 10 days. If you happen to fall into a job that requires 2 additional individuals for 45 days it could cost you an additional $400 or more (based on pricing I was given back then) that you'd need to include in your job quote.
Ask these same questions to each underwriter/agent as each company/agent handles this differently so some charge a yearly fee, some charge a per request fee, and others don't charge any fees. For instance, when I had Central Insurance as the underwriter, my $1,000,000 policy was $800 the first year but by year 5 of coverage with them it was up to $1,200 plus an additional $300 for a pesticide rider. The cost for certificates of insurance was $0 but the cost to add an additional insured was $150 (if I remember correctly). While this wasn't a cheap policy, what it did do was cover any employee/worker/uninsured subcontractor I had regardless if they helped me for one minute or were a hired employee working full time.
Also, make sure that you get a copy of the policy that specifically shows coverage for you regardless of who you go with. That way you can see specifically what is covered and more importantly what isn't. It also proves that the policy is specific to you (or your business if your incorporated) and that you aren't part of a group policy where others could use all of the money leaving nothing left to pay a claim that you make.
