I keep getting bubbles in my silicone

So I've decided to build my own tank. I currently have a 2ft and wanted to go up to a 3ft but none of the pet stores nearby had any so I bought the glass myself - this way I could also make it slightly bigger (90x40x40cm) then their ones (90x32x32cm)

I followed the method given in the following video:
[video]https://www.google.co.za/url?sa=t&rct=j&q=&esrc=s&source=video&cd=2&cad=rja&uact=8&ved=0ahUKEwjnqoXoiZ_JAhWLuRQKHfq4B00QtwIIHTAB&url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DO2VhiH3Ou0w&usg=AFQjCNGJocmiH1FgsDxDdAjL44k6skfS cA&sig2=uj5oKC5JnZfRw8GnKbvKmg&bvm=bv.108194040,d.ZWU[/video]

I've now built it three times, but each time there are lots of bubble in all of the seams, I'll add the pictures below.
The only thing is that I don't have space to fit all of the glass at once so I had to put the base on a piece of wood, attach the first two pieces (the front and left), then carefully turn it around before attaching the other two pieces.
I'm sure it's best not to move it but could this small bit if movement really cause so many bubbles in the seams?
I cleaned the glass as thoroughly as I could using methylated spirits. I found on the internet that someone suggested it so on my third attempt after using meths I also wiped the glass down with a damp paper towel, then dried it with another dry piece.
On the third attempt I used wooden jigs I had made to clamp the corners together to align them and keep them from moving but that obviously didn't help.
I'm also using the Bostik aquarium silicone you find in any hardware store.

What could I be doing wrong?
The only thing I can think of is to somehow find I place big enough so that I don't have to move the aquarium while building it, and find a different brand of silicone, maybe something of a higher quality.


The pictures aren't great but you can clearly see the bubbles running along most of the seam.
Mostly it's lots of tiny bubbles but in one or two areas there were some clusters of larger ones.

Also, some of the inner joints are a little rough because I waited too long to pull of the masking tape, but that's another issue.

 

Hi and welcome, your pictures does not show, try re uploading them please.

 

Strange, they showed up at first and I can still see the thumbnails.

I can't see any way to edit my previous post so I will add them again below.