Your powder weight can vary due to the diameter of the bullet. Berry's 230 grain LRN have a diameter of 0.452 inch and it's recomended that they be loaded at low to mid range data for jacketed bullets. Some of the other plated bullets feature a 0.451 inch diameter and the usual recomendation is to load to dat for lead bullets.
I recently picked up some HSM bullets from Midway and as they are 0.451 diameter as stated by the manufacturer and confirmed with micrometers I've been using data for lead bullets. Initial test loads were tried at 5.1 and 5.3 grains of Unique with an overall length of 1.265 inch. While they functioned just fine in my 1911 they were noticeably soft shooting so I stepped it up a bit. My final load is 5.5 grains of Unique and an overall length of 1.260 inch. It's still a bit soft shooting when compared to Federal Champion but the accuracy is quite good and I don't see any need to go any hotter. One reason for not going any heavier on the charge is a warning from HSM to not exceed 800 fps with their 230 gn plated bullets, apparently if you push them too hard you can strip the plating off. Another reason is I'm cheap, it's a very economical load and my brass will last for many many cycles at this low pressure.
BTW, I dropped the length to 1.260 specifically because the 1.265 length was a VERY tight fit in my recycled Federal Champion boxes so I shortened them up to match Federal's OAL length. I'll also note that I've broken down a round of that Champion that had a sideways primer and found that Federal is actually using plated bullets that appear to be identical to the HSM bullets I'm currently loading. As for results at the shorter length, there are absolutely zero indications of excess pressure and the blowby stain on the fired hulls is basically a match to the lighter loads at 5.1 and 5.3 grains.