Why a Twin ?

If a single engine aeroplane is cheaper to build, maintain and run. Why would you want a twin?  Seems pretty conclusive so there must be other reasons to take on this project.

There is the whole safety argument of having as spare engine if one stops.  The counter argument to this is, all the good engine will do, is to get you to the crash site sooner.  True only if the pilot does not maintain their currency in engine failure after take-off drills.  Having my own plane, flying it regularly, maintaining my emergency procedure currency, then having a second engine should be a positive.

If I make best advantage of the rules that govern, designing, building, maintaining, (and yes flying too) an experimental aircraft, I hope that many of the associated costs (relativity speaking) can be kept down to within budget.  So compared to other experimental aircraft, yes it could be more expensive, but compared to even single engine certified aeroplanes, it would be cheaper.  Let alone any comparison to a certified twin, it would win hands down on cost.

The real reason to have a twin is to log multi-engine flight time in the pilot's log book.  It is the Australian experience, that employers value multi-engine time over single engine time.  Enshrined in the Civil Aviation Orders is a rule that requires pilot to have 500 hrs PIC multi-engine time prior to upgrading from a first officer to captain in a low capacity regular public transport operation.  For the Australian market you need those 500 hrs PIC multi before you even get a look in at a first officer position.  So if one day my kids did want to learn to fly, this would be the way to go, so all their flying is multi-engine time.