There was a discussion on this subject on the Stirton Forum recently. The concensus was that for pistol it was better to shoot same hand and eye rather than to try and match dominance. This presumes that the non-dominant eye is "fit for purpose", if not it may be worth trying the non-dominant hand before going down the offset grip route.
Rifle shooting is a bit different and there are 2 answers to the problem available, either a prismatic periscope or offset sight blocks. Gehmann produce both, the Gehmann Crossover Prism ISSF Legal 597 and the Gehmann Sight Displacement Blocks 857. They can be seen here on the Intershoot website.
There are advantages and drawbacks to both solutions but I have seen both used successfully over the years.
Hope that this helps.
Rutty