Clamping braces into an assembled Cab

[TheGameFan]

I am building my first cab from scratch and I got a little over anxious putting it together. I glued everything together, but used very little bracing between the pieces. I made a 2x3 box mounted to 3/4" plywood for the base and have a 2x2 brace running at the seam of the top to the back, but I really don't have anything holding the sides to the top to the or back (aside from the glue between the pieces).

Besides the braces I mentioned previously, there is also a 2x2 running from side to side below the control panel and another above where the coin box would be. The sides are 5/8 MDF and the back, bottom, and top are 3/4 plywood. Is this enough support? It feels pretty strong as-is, but I noticed most cabs have 1x2's along all of the seams.

Since the back is already on, I can't figure out any way to clamp 1x2 or 2x2 strips in the seams to give support (clamps are only a few inches deep). I could use metal angle brackets, but I'm not sure how effective those would be and they would likely accentuate my "noobness" to anyone looking at my cab.

[BobA]

You can fasten the strips in place with a brad nailer or short screws from the inside.  These can be left in place and when the glue dries everything will have extra support.

[ChadTower]

You can fasten the strips in place with a brad nailer or short screws from the inside.  These can be left in place and when the glue dries everything will have extra support.

That's how the original cabs were made anyway.   

[DNA Dan]

Get a Kreg mini pocket jig and create as many interior braces as you like.