I would recommend reading up on the floculation method for determining when to cut your cheese and also how to adjust your rennet amounts.
It's actually pretty simple. First, when you add your rennet to your milk, float a small plastic bowl on your milk surface. Something like a small tub that cottage cheese comes in. If you nudge this, it will sail around quite freely.
Every two minutes, tap it. Eventually, you will notice it doesn't float so freely, more like it's wading through thick mud. Start nudging it every 30 seconds until it just sticks in place; like it's got it's feet in glue.
That is the point when the milk has "gelled". Check your time. What you are aiming for is for that gell time to be 10 to 15 minutes after the point you added your rennet. If it's faster than 10 minutes, use less rennet next time. If it's longer than 15 minutes, use a bit more. This allows you to adjust your rennet to your milk. Since you're using raw milk, you will also find things like seasons, time since calving, etc, will effect how the rennet and milk work together. Just keep notes.
Anyway, let's say your gell time was 10 minutes. Different cheeses have different "multipliers" associated with them. For example, cheddar uses a 3x multiplier. That means, multiply your 10 minute gell time by 3, so 30 minutes, and cut your cheese 30 minutes after adding the rennet (do not forget that you've already used up 10 of those minutes just getting to the gell time.) You then cut your cheese at that specified time, rather than testing for a "clean break".
You can find on this board information about the multipliers for specific cheeses. But the general rule is, the moister the final cheese, the larger the multiplier. Cheddar =3x, camembert = 6x.
It takes longer to explain than do.