“Figure your drainage and any exposure to standing water carefully.”
I personally do not like gutters or downspout. If you can raise your slab/building enough for really positive drainage, and extend your overhangs enough, I would go that route along with some additional in ground drainage. Big overhangs and positive slope go along way!!
From the $$ standpoint and long term maintenance that is my preference. My secound choice in your situation where gutter cleaning is inconvenient due to hight, here's what I did.
(A) Keep overhang short so that runoff fall's near wall. (B) Instead of mounting gutter at 14',mount it at a hiegth that's easy to reach with water hose wand or step ladder. Use blocks of treated lumber at each gutter bracket to position gutter to catch water. Paint gutter,downspouts and blocks exact color of building.
To manage water after reaching ground level,I helped my bil set up an above ground pool he got free off CraigsList. It's shocking how many gallons even the smallest pool stores when compared to # of 55 gal barrels and 275 gal totes required to store an equal amount. In his case,his vegitable garden,part of landscaping and a livestock watering tank is lower than ground where pool sits near building. We buried 1/2" pvc running to hydrants which gravity flow. I leave it to you watering plants with public water and compare to others watered with rainwater. Same is true of livestock. Unless starved,livestock will stand next to a bucket of public water waiting for empty trough to be filled with rainwater. Composters are aware of benifits of rainwater over public supply. The set up worked as planed but after 2 years,he saw room for improvement. Mosquitoes raised in pool,in rainy season when less water was used,pool overflowed making ground wet and soggy plus he tired of explaining why his swimming pool was in such an odd place. Back to CraigsList for free retaining wall/landscape blocks,flagstone,gravel and river boulders to create a natural look pond (inside and outside). Various native minnows,fish,frogs,mussuls and water bugs keep it clean, control mosquitoes and intertain. To minimize overflow,a buried 2" pipe discharges several yards away downhill. During shoulder seasons,skimmer ties into drain pipe. Dureing wet as well as dry periods,a manifold of pvc pipes and ball valves are adjusted for desired storage level.
