On these brackets, there can be quite a lot of force. It is a good idea to use big washers on the inside of the velomobile shell. That virtual crossing point is very important, for the steering behavior of the velomobile. I had a scary experience when i braked 1 handed/single sided at 50 km/h on a 2 meter wide bikelane.
Just elongating the metal rods with a dowel or stick can be helpfull, then drop a plumbob from the crossing point. Placing the mounting brackets a bit forward, or outward can have a lot of influence, the line from the front rod also pivots around the balljoint on the steering arm.
I'd count on having to play with it a bit before permanently glueing things on.
I started by getting the wheels flush with the body, with the centre rods. Then from that adjusted the front rods, to get the wheel centered in the well. Then get the wheels paralel by measuring underneath the body, get the same distance at the most forward and rearward spots where u can get the tapemesure under the velo. Then final micro adjustment of the tracking with a slow speed rollout test.
At least play a bit with brakes and steering at slow speed before plummeting down that hill at 70 km/h.
Greetings, Jeroen