This only works with the lighter bullets in that caliber. Hodgdon has youth loads, using H4895. You take any load where H4895 is listed, and multiply the max charge by 0.6. That is as low as you can go. This will be much lower than you want to go, but you can use any charge in between.
Checking their site, they have data for h4895 up to a 168 gr. bullet.
For more info, see the youth loads on the Hodgdon site.
http://www.hodgdon.com/PDF/Youth%20Loads.pdf