As Steve and ITO mentioned above, you are giving one lump sum price for performing the electrical design and the construction work. Make sure you estimate the design effort, and include the cost of the seal if required. You need to know if sealing is required before you can quote. You need not do any more than a basic preliminary design or layout - just enough for you to estimate the construction work.
Stick with this - "My price for the electrical design/build is $xxx". Don't break your price down into parts if at all possible, and that would only be if you had to agree to do so before hand.
You should make sure the contract makes allowance for setting up a schedule of values. You can then get paid for your design effort and costs before the construction starts, if there is a time lag. Churches tend to have less than firm schedules, due to funding and other issues.
Generally, as a rough rule of thumb - we figure electrical design and sealing to be about 10% of the construction work. However, this is a very old rule, and there are a lot of variables. You will likely be responsible for plan check fees too, so go make friends down at the local neighborhood bldg dept.
Good luck,
Radar
