Longer insert protocol

[TonyBrooks]

Hi all
For standard DNA preps, we've been happily using the NEBNext kits with Covaris shearing (Agilent protocol) AmpureXP bead size selection (from the NEB protocol). This usually gives us insert sizes of around 2-250bp, which is fine for HiSeq 2x100 sequencing.
Now we are going to be sequencing a few bacteria strains on the MiSeq with 2x250 reads. Obviously, to make the most of this we're going to need a longer insert size (greater than 400 would probably be OK). Has anyone optimised a gel-free protocol for longer genomic library preps? I was thinking about using the size selection protocol from the 454 rapid libraries (target is 700bp), but the only thing putting me off is the last time I did 454 libraries, I had them approaching 1kb (which would probably be OK on the MiSeq, but I'd prefer inserts to be a bit smaller).
Thanks

[TonyBrooks]

FYI, I tried tweeking the NEB protocol with some success. I now have a library peaking around 390bp (insert size of 260bp).

a) I sheared to 300bp on Covaris.
b) Size selected between 0.6X and 0.8X AmpureXP
c) Increased PCR extension time to 45 seconds (probably not necessary)

The library is definitely bigger, but I may try a 0.5X-0.6X Size selection next time to minimise the fragments below 300bp and tighten the spread.