Oh Boy.... The old overhead/profit/costing issue.
Way I see it, you are asking two different, but seemingly related questions.
One is an accounting issue of how to allocate overhead costs. In your case, as a startup, would be to estimate accurately your OH costs, and allocate them to your estimated jobs on probably either a revenue or time basis of each expected job.
Yes, viewed in this manner, I guess it could be argued you are charging your customers for your downtime...but that is really irrelevent and only an accounting concept.
From a business perspective, which should be your major concern, you want as much "contribution to OH and profit"(rev minus labor/materials) as the market and your services will bear.... ie get the best price you can.
That should be your focus.
Assuming you want to remain an ongoing business, it will help you to know if you are at least covering your OH costs in your (contribution to OH/profit" estimate. Because if you are not, you will not have long term survival/prospects.
But as a start-up, with low volume, you may encounter instances where you are not covering your OH allocation on a job (why... you can't get a better price at the time or as a start-up). It can still be beneficial to take the job.... you will be loosing less money than not taking the job. (This is a short run start-up consideration only)
For instance, let's say you have 5K annual estimated OH... and you estimate that you are going to have only 2 5K cost/value (reflecting normal OH allowances of competitors) jobs during start-up.
If you were to allocate 2,500 to each 5K job, you'd price at a minimum 7,500 per job (for break even). Assuming the jobs are 5K value, you are not going to be competive with a 50% premium. You will not get either job and loose your OH of 5K that year. If you take/get the jobs at say 6K (below your allocated OH per job estimate) you would have 1k contibution per eash job and only loose 3K that first year.
This is the concept of a start-up with out sufficient revenue/volume to cover it's OH.... think numerous internet ventures (Facebook) that have not made money in their first years.... they can't pass their full OH costs thru to their advertiser (in this case) on their start-up limited volumes.
This is mostly conceptual to your instance, but I think important to understand. In your case 1) your OH should be kept to a minimum and realistically you should be able to cover it even on low volume... but by the same token, don't expect you can price a year's worth of your F350 depreciation into your several/limited deck jobs that you estimate you might have the first year.
Bottom line, know your OH (and other costs), and whether you will be profitable in the long run, BUT price as high as you competitively can
to contribute to your "OH and profit" as a start-up.
Best