If you want to stay with the current lofts which are more on the traditional side, the only thing you can do is go lighter with the shaft. There are a lot of steel and graphite options that are lighter. The DG R300 is 127 grams, so you’ll want to look at at least 110 grams and below and will probably need to go lighter than that to be able to see any difference. Loft will influence distance in irons far more than just lowering the shaft weight and thus the overall weight of the club. If you want to play the same heads, going lighter and even slightly longer in length are the only options to try and pick up a few yards. Again, a lot of options in steel and graphite to choose from (too many to list here). If you search and find a few you may want to try, let me know and I will give you an opinion on the choices. Look at Nippon for really lightweight steel, and UST Recoil or AeroTech for multiple weight options in graphite. There are others, but that is a place to start.