Bruce I use 18.5/H110 /125 in my 30/221and get 1950.Ohter friends who shoot 30/221's use 19.0/H110/125 and 2050. The little gun should burn about 5-8% slower than H110 so you should be able to go 19.0-19.5 at least with LG. I have some LG also and have not had a chance to load it yet in my 30/221. I determined my max loads by measuring case heads , just in front of the extractor cut , ususally .374, and I have found any load that bumps the case head greater than .376 is too hot and enlarges the primer pockets. I would be interested to see what you get velocity wise with the 19-19.5 range of LG and the 125 BT.
Keep in touch and let us know about your experiments. Jim