Hello, Bwananelson:
I do not know exactly with what bullets the rifle was regulated. Mine makes very good groups, much less than one inch at 50 m with each barrel . It shot a little too wide for my taste with the 270 grains Hornady Core-Lock ammunition, 3-3,5" with the two groups level and better with Sologne GPA bullets (a solid copper banded bullet, made in France, very similar to the Barnes TSX). I know another Sarasqueta of the same vintage, identical to mine and probably to the one you have, that shoots very well with the Hornadys mentioned. You can begin trying with that ammunition.
I re-regulated mine with factory Norma Oryx of 300 grains, if I ever go to Africa I would like to shoot the heavier bullets.
Mine balances about 1,5" forward of the hinge pin, weights 8,5 pounds. It is very comfortable to shoot and very steady offhand.