As the Penrite steering box lube is a very thick semi-fluid grease,you could try putting some in an oil gun(similar to a grease gun,but designed for thick oils),or put a small amount into a plastic bottle,microwave it for 30 seconds at a time til it's fairly fluid and easy to pour,then fill the steering box up to the bottom of the grease nipple hole.
This the best way I've found to do the steering boxes in my '28 truck & my '29 Olds.