Not a stupid question at all. I would leave the roof in place, it is such a quick and dirty test you don’t want to be dismantling hives every time.
As you are only trying to tip up slightly from one side at a time ( you can do one side then the other if you think the syrup has has been unevenly stored ), the difference a roof makes to raising a couple of cm is negligible. You are really briefly testing resistance to lifting rather than “weighing” as such.
Weighing, if desired, is probably better done with eyelets in opposite sides of the floor and luggage scales or the like. I have not personally done it.
As mentioned, colonies often consume stores at different rates. Hefting say every couple of weeks or monthly quickly picks up those colonies going lighter than the average and flagging up if they need extra help. Conversely, some stay stubbornly heavy - if this is combined with little or no entrance activity on the days when others are freely flying, there may be an issue. The latter case is arguably more annoying as in the middle of winter there is usually little you can actively do.
As you are only trying to tip up slightly from one side at a time ( you can do one side then the other if you think the syrup has has been unevenly stored ), the difference a roof makes to raising a couple of cm is negligible. You are really briefly testing resistance to lifting rather than “weighing” as such.
Weighing, if desired, is probably better done with eyelets in opposite sides of the floor and luggage scales or the like. I have not personally done it.
As mentioned, colonies often consume stores at different rates. Hefting say every couple of weeks or monthly quickly picks up those colonies going lighter than the average and flagging up if they need extra help. Conversely, some stay stubbornly heavy - if this is combined with little or no entrance activity on the days when others are freely flying, there may be an issue. The latter case is arguably more annoying as in the middle of winter there is usually little you can actively do.