Heteroduplex mobility assays

[Dr. J. Green]

Hi,
We're looking to use HMA to analyse small PCR products, the smallest being 120bp.We've tried Metaphor agarose and the PHAST PAGE system but haven't got particularly good resolution(we can differentiate products with upto approximately 80% identity but would like to raise the resolution to 90% identity). We could use standard PAGE gels but would prefer to use agarose. Is that feasible on products this small? Can anyone suggest alternative media.

Any help appreciated 

Thanks

Jon Green