1st Gen DC rear seat spacer?

What's up guys? So I built a box for two 8's that fits behind the rear seat exactly. As in it fills the entire area so well that the subs contact the seat cushion. I ordered some grills but I need more space, even a half inch would work perfect. The problem I'm having is that the rear bench is attached with 2 bolts in the front that run almost horizontal and 2 in the rear that are vertical. So if I put a half inch spacer on the front it would pull the back forward. Anyone done this before or have a solution?

 

You can elongate (make oval) the hole opening on the rear brackets so the seat slides forward and still can be bolted down. I don't recall how close the hole opening is to the edge on the rear bracket but it's worth a look to see if you can do it. Let me know how it works out as I'm also re-doing on the stereo in my dbsb. Pics of your sub box?

 

I'm going to try that this weekend and let you know. That's a really good idea.