Billy Goat AE401H maintenance questions

I am reading the manual for my aerator about how to perform the maintenance.

I had a few questions:

1. They say to use a grease gun to lube the bearings. I didn't use that. I used this type of oil that I get at a rustproofing center and it is oil that can be used on anything. Should I hit the bearings again with the grease gun or am I fine?

2. They talk about adjusting the belt and chains. I know how to do that, but when they tell me 1/4"-3/8" chain slack, how does one know that? I usually just gauge this. Is there any other way to really know? I just gauge by fingering the belt or chain to see if it has a bit of slack. I use my common sens on this.

Bearings need to be greased, oil will not protect then and the heat will dissipate the oil very quickly. Chain and belt slack can be measured by placing a straight edge accross the pulleys or spockets and then measuring the slack when you push on the chain or belt.

Thanks Rivets! I will hit the bearings with grease gun and measure that slack.