Does anyone have some decent loads for the Whelen with a RCBS 35-250-SP? I an thinking I will start at about 38 to 40 Grains of IMR 4064. Opinions?

Try the 4895's (H & IMR) in the same quantities you are thinking for 4064. I have used 4895 a lot with cast bullets from 250 to 287 grains. Not hard to get excellent accuracy with an air cooled WW bullet in the 1850-2000 range. My bullets are Lyman 358318 and NOE clones and Lyman 358009. Use a quality lube like Carnauba Red or similar and size .002 larger than bore to start.

I also have a small amount of IMR 4895 in stock and will try that as well, Thanks.

40 gr 4895 or 30 gr 4227 are very accurate and will shoot about 1900 out of a 20" barrel.