It won't hurt the bullets too much to size them .005, but probably the spread won't be that large if you keep bullets fat as possible so they will still chamber, which is the best way to size anyhow.
What I like to do for customers like you is to have you send in throat slugs from all the rifles, so I can make a bullet which suits all of them if possible. Normally I can give a near perfect fit to most, and a decent fit for the worst, all in one mold. But I do have to be given the reins so far as bullet weight. When making a mold for several guns I cut the length to suit the shortest throat, and diameter of the base to fit the largest chamber, with diameter of the nose drive band to suit the largest groove diameter.
If the customer mandates that weight not go below a fixed minimum, I may not be able to fit all guns with one bullet, but we can comunicate on the options after I measure up all the slugs, if that is a customer concern.
Then there is a simple solution. Order a .314 diameter 170 LFN, which is a relitively short bearing bullet as 30 calibers go, and it's a tough one. Just use it at the largest diameter you can and get them chambered easily. This without going to all the work of makeing up throat slugs. If one of the guns, or two, don't thrive on it, make the throat slugs and learn why or order a mold to suit just those, if it seems worth the coin. In the long run, results will probably be close to the same, with a bit more tinkering to get the right sizeing diameter, but less makeing throat slugs.