I wouldn't throw that 1/2VW away just yet.

Don't intend to. If I keep switching boats in the middle of the stream I may
never reach shore. But once the thing flies the way I want the 1/3 'Vair might
be an "upgrade". Even though I have lots of VW experience I see some
advantages to the "vair - like proven hydraulic valves and a better place for
the second plug. (IMHO there is NO good place for a second plug in a VW)

The 1/3'vair looks neat but it has less cubic inches then the 1/2VW

Not if built with 103mm or 105mm VW TpIV pistons.

And is heavier.

Probably. But how much heavier than a 1/2 VW made with the new all aluminum
case? I'd trade a few pounds of weight for a case that didn't crack or commit
suicide when it gets hot. Not that I ever intend for it to get that hot.....

And the heads are MUCH easier to modify.