Have had one for several years now and have thrown several hundred clays. Assembly is not complicated if you can manage simple hand tools - sockets/end wrenches - they do supply some simple wrenches with the unit. Because people sit on it and it vibrates when the clay is thrown periodic tightening of the nuts/bolts is needed - but its really not an issue. Yes it can throws doubles. I shoot a single barrel trap so doubles are not what I need but friends have pumps or over/unders and you can place the clays side by side - never tried on top of each other as others said. The arm 3/4 cocks itself each throw so the final pull to the locked position is not difficult - a woman or teen can do it. However I would thoroughly instruct the person throwing on safety. Once the arm is cocked and held in place by the pull lever - if that lever is pulled/bumped or caught on clothing the arm rapidly and powerfully spins out. I can see how it could break a finger or leave a nasty bruise if that arm hit a human body part.I put the supplied wrenches o a "pear" clip and attached them under the seat - I do not use the tow-hitch attachment as it sits too low for me to use easily - a truck might be higher than my UTV. - overall it works for me a recreational shooter. Not strong enough for commercial use or club use.