Last night I trimmed skins to size, deburred, cut out slot in trim tab spar for control rod and filed all the edges.

I'd seen other people use a Dremel tool to do the control slot - I don't have one (used to, think I lent it to someone!!) - but found that a step drill, used carefully and with wood clamped behind the aluminium, worked fine.  Even on the 0.016 skin.

I also made a doubler (just 0.016) for where the trim servo is riveted to the top skin.  

Still need some minor trimming of rear skins - they overhang the spar by about 2mm so will cut them down to size.  After that, I need to get everything back together and make the control horns & centre hinge point.  Then disassembly again and priming before final riveting.  Always takes longer than you think it will!