:) Got your PM. That does look like quite a substantial gap doesn't it!
Really is a bit of a tricky one. Look like you would have to machine the rocker posts, but you really don't know how much you should take off them until you've had some oil pressure in the lifters.
Can't say I've ever really seen anybody build a similar combo, so you just need to be a bit of a 'pioneer' really. Atleast when you do get it sorted 100% we will all know, and then this info can be added to the FAQ for anybody who might want to go down the same track.