power directly off of Panels?

I agree that there are too many variables.  Maybe your least expensive option would be to get a Marine Deep Cycle battery from your local big-box department store.  Keep in mind that for best battery performance (life), avoid discharging it below 80% of capacity. 
   

 storing the extra 20w an hour?

there is no such thing as watts per hour.  watts is a rate = joules per second, not a quantity.  watt-hours is a quantity.  this causes much confusion and is a common mistake.

first off, with a 60w array, anything above 40w instantaneous is great, as 60w assuming stc is unlikely.

second, unless your load is designed to run pv direct, you will want a battery.  you compare your watt-hours per day of load to your watt hours per day of production.  the latter must be higher.

third you must decide how many days of autonomy you would like. your battery must be able to handle the watt-hours of load for as many days as you want your system to work in absence of sun.

there is more, but this is the basics of off grid system design.  we talk at length about these topics in the courses.

if you tell me watt-hours per day of load, and days of autonomy that you want, i can suggest a battery and array for you.

cheers,

james