A historic article regarding our school district's earlier years noted that a lighting rod had been included on a student' supply list along with candles and firewood. Why a lightning rod?
It will provide a cone of protection with a ground radius of the approximate height. So if you want to protect everything within a radius of 25', you want to mount it 25' high. A blunt one will provide better protection than a tapered one. As far as size goes, that may well be determined by the code where you live.
When mixing with water, sulfuric acid should always be added to water, never the other way round. As a strong acid and an oxidiser, sulfuric acid should be stored away from bases and reducing agents. It is highly corrosive even when dilute, attacking many metals such as iron and aluminium. Gloves and goggles should be worn when handling dilute H2SO4, and the concentrated acid also requires use of a face shield and PVC apron. Always wear safety glasses. Do not allow the acid or a solution of it to come into contact with your skin. Concentrated sulfuric acid acid should not be diluted by inexperienced users! When diluting acid always wear eye protection, and ALWAYS add acid to water (not the reverse) slowly and with great care. Use constant stiring (sulfuric acid is much denser than water, and if you do not stir when adding acid to water, a layer of concentrated acid may form at the bottom of the beaker, creating a substantial temperature gradient where acid and water meet). Note that freshly-prepared solutions will be warm or hot, and will as a consequence be more corrosive than a cool solution. If you need gloves, use neoprene, butyl rubber, natural rubber, polyethylene or PVC for handling solutions at concentrations of up to 70%. Use butyl rubber or polyethylene for concentrated sulfuric acid.