A home with fewer rooms may have an extension, several gutter levels or a difficult rear passage. A larger building may have straightforward visible runs. Give the actual layout and requested sides instead of expecting the bedroom count to determine the work. Safe wide photos can show the main house, lower roofs and the area beneath the gutters.
You do not need exact measurements taken at height. State what is known, name the affected sections and explain what the photographs leave out. If a pipe is hidden behind an extension, say so. A useful quote starts with enough information to ask the right access and scope questions, not with a guessed length for an unreachable channel.