This is my solution for mounting an RTL510 or RTL515 onto a Topeak Wedge Quick Clip saddle pack using a piece of stainless steel and a couple of screws to hold it in place. So far its survived a few hundreds miles on England's finest bumpy country lanes and is still solid as a rock.
I bought a piece of stainless steel sized 35mm x 160mm x 1.2mm and drilled holes in it to match those in the quick clip, then sandwiched it between the upper and lower halves.
The quickclip comes apart with just a single screw but to give it a bit more strength I drilled right through the screw hole and used an M4x20 button head stainless steel screw with an oversized washer inside to spread the load. I also drilled another screw hole and use an oversized washer towards the rear of the pack for a bit of added strength.
I used a k-edge replacement insert with longer countersunk M3 screws to attach the Varia to it - there are cheaper alternatives on Amazon etc but k-edge have the best reputation IMHO
To bend it, I used a couple of clamps with blocks of wood to grip the end to my work bench (alternatively you could use a vice) so I could bend the end over, I'd recommend clamping the small end (where the light mount will go) and pulling the long end as its a lot easier.
Finally I applied a couple of coats of primer and satin black paint to finish it off
parts list :
35 x 160 x 1.2mm stainless steel sheet (I suggest 180mm long for a large pack) - mine came from 'the aluminium shop' on ebay UK , who kindly cut it to size for me - www.ebay.co.uk/.../thealuminiumshop (other sellers are available).
K-edge mount k-edge.com/.../
Topeak quick-clip saddle pack (this one is an expanding wedge, size medium but as far as I know the clips are all the same so any pack which fits your bike should work.
www.topeak.com/.../361-wedge-pack-ii
M3x8mm countersunk screw and nyloc nuts, M4x20 flat head screws and nyloc nuts - I happened to have all of these anyway but have used Kay's fasteners on ebay many times before www.ebay.co.uk/.../kayfast1 (other sellers are available)
