I use a laser firm close to me, you also need a deep pocket. With the machines costing upwards of £100,000.00 the need to recoup that outlay has to be factored in. The CNC rotary fullt automatic, cast £500,000.00.I have no direct experience but have heard good things about using the new generation of handheld laser welders which seem to allow even novice fabricators produce high quality joins . The advantage for Aluminium is supposedly a clean and fast weld with a very small and limited heat affected zone and depending on the head used a wide "wobble"bead can be produced . A1500 Watt machine is ( I am told) capable of producing a weld depth of up to 10mm in aluminium. Maybe a local search to see who has appropriate equipment and experience would be worthwhile but I understand the reluctance to commit as you will only get one chance and it must be right first time.