Purchasing items via these affiliate links supports DoingWhatever at no extra cost to you. Thank you!
This can be modified to whatever dimensions you need - this is just what mine measures out as.
The most important dimensions are the 135 and 90 degree angles on the left side (if you're going for a 45 degree set-up). The other important dimensions are the groove cut out dimensions for the rail - they should match/be snug.
The pieces that join the two sides look like this. I put a random angle on the two top pieces to better craddle the router.
Different angled view - the circles represent the holes drilled out for the worm gear hose clamp.