The Walipini Project (aka greenhouse shenanigans)

I've used aluminium sheet, cut in strips and bent to form the Z clips in places where ordinary Z clips are not long enough, you might want something with length to get a decent run out to the gutter.

Rebating that lot with a router is going to be messy and make sure you dont inhale the dust if its treated especially.
If you get a new cutter I'd go for a rebating cutter rather than the general purpose fluted cutter.
Similar to this but there are lots of others.
Trend TR34X1/2TC Bearing guided rebater 12.7mm

Kind of depends on what size rebate you want.

 

Half inch shank?

 

Remember to allow a sufficient air gap to permit draining of condensation betwixt glass and bottom rail. My 'borrowed' walpini had wooden block secured with brass rhd screws to hold bottom sheet of glass, one centrally.

 

Not suggesting this by any means, but I do remember seeing in old wooden glass houses that in the real classy ones the bottom edge of the roof glass was curved so that the rain ran down the centre rather than rotting the glazing bars.
Just thought I throw that in.

Any body got a glass cutter.

 

Finished rebate depth needs to be ,say, 2mm above the bottom rail.Not more to reduce draught, not less to hold bead of moisture.
Glass held by block screwed to the rail.
No drawing skills!

 

I'm not really that up on wooden greenhouses, yes you get a gap under the glass on ali ones, but I'm just wondering how well the condensation runs out from under the glass in a wooden one.
Doesn't it soak the top rail/wallplate and rot it away very quickly.