10mm versus 8mm Y frame on 'improved' mdf frame

My first project with my recently completed Prusa I2 is to print parts for a Prusa I3...
I bought a laser-cut melamine-coated 6mm MDF frame on ebay - its the 'improved' laser cut frame by twelvepro (http://www.thingiverse.com/thing:39889). The one I have is pretty nice. Problem is, current I3 builds seem to use 10 MM threaded rods for the Y axis, whereas the slots in the rear supports for this frame are 8mm wide. I printed one of the original 8mm prusa corners and its a good fit with the frame, and I printed one of the twelvepro corners which are 10mm and it doesn't fit at all . So I have a range of options and I'm not sure which is the best way to go:

- should I get the router out and modify the frame for 10mm rods ?
- should I just go with the standard prusa 8mm corners and 8mm rods all round?
- should I build some sort of hybrid with 10 mm 'long' rails and 8 mm 'short' rail at the back using some custom 8mm/10mm corners?

any thoughts?

Stick with the 8mm. If you need extra strength due to a larger build area and are afraid of your rods "sagging" in the middle then use 8mm Drill Rod from McMaster carr. it is rigid beyond belief and cannot sag. Be prepared to take your time cutting it to length, the rod is stronger than your hack saw blades (use a cutting wheel on a hand grinder instead)