Raising truss bottom braces in 'shed'

[MisterBoy]

I'm recovering this old Victorian greenhouse, the top part totally replaced on existing brick base. Approx 5x2.75m

I got someone to help with the roof and they added 3x2 cross braces as it was not rigid enough.
Now I'm panelling it out, I would like to raise the braces for greater height, about half way up the truss.

I'd cut them angled to fit snugly, are they better screwed, nailed or bolted? I'm assuming on a 2.75m span (30 degree pitch) that would be plenty strong... The main roof structure is 6x2 with a 6x3 ridge, using bitumen sheets. It is exempt from building regs (I've checked!) but obviously needs to be solid.

 

 

[big-all]

if you take the top picture and the second one down from the picture top and the position transposed to the 3rd one behind it looks about right to me

 

[MisterBoy]

if you take the top picture and the second one down from the picture top and the position transposed to the 3rd one behind it looks about right to me

Thanks, that would be about ideal actually.
Would I be best screwing perpendicular to the angled piece, or perhaps mending strips (if that's the right term I've never used them) are better like you see on fabricated trusses?

 

[big-all]

12mm ply Gusset plate either side or just overlap and loads off screws and or bolts and toothed dog
the only load on it is trying to stretch it small ish dimensions[3x2 or 38x69mm cls] but good fixings