If you are going solid roller then there is a type of break in you want to abide by. Solids need to be lashed hot. So the base setting you lash at cold will need to be slightly tighter on an iron/iron combination and way tighter on an aluminium/aluminium combination. So if the lash is around .020/.024 on a iron head iron block combo I'd set around .016/.020. If it was an aluminum head and aluminium block I'd be in the .010/.012 range. Lots of growth occurs from cold to hot. After the motor gets hot and up to operating temp on the water AND oil, then the lash has to be run and set to proper specs.
Cold starting points should be verified with the camshaft manufacturer, but will always be less than the hot spec. If your too loose on the initial lash you can bang up the lifters and ramp of the camshaft.