With Echo Lite forks mine was 1005 and +45, so with Onza forks it should be 1025 and +55 by my reckoning. They are the increases that my Zona's geometry changed by when I swapped the forks to Lites. I'd change the forks first if I were you. If they are the same forks as T-Pros, then they weigh 1.4kg, or at least mine do, I can't shift them haha. A set of Echo Lites is about 820-840 with a cut steerer I think, so you'll be saving over half a kilo. I'd do this before the front wheel, I had an Onza T-pro one, so it should be the same as yours, and it wasn't all that heavy. I'd change the stem to something like a Try-All with 0-10mm of stacks under it, I had mine at 20 and it was a bit too low, but I solved the problem by getting Monty PR bars.