Hi Monty,
Yes, different sources of milk will respond differently to the cultures and rennet. A good example of why using measurements that indicate how this particular make is going are better than using average values obtained by someone else using their milk and rennet, etc.
Your cheeses look nicely formed. Four months should be a good time to taste, though I know some people will say that if you can hold out to 6 months then it's worth it. Still, with 3 more gouda's in reserve, you're probably ok to get rid of temptation by giving into it!
If you do cut it into it ... hey wait! Come back, I'm not finished and put that knife down this instant!
Now, as I was saying, if you do cut into it, after cutting your wedge let it come to room temperature before slicing further and tasting. I often find that the cheese really needs to breath for a while after taking it out of the wax, so you may want to cut it, remove the wax from your wedge, re-wax what you're not goign to use, then go out for awhile to let the cheese breath for couple hours (keep it in the cave, where the humidity will keep it from drying out), then when you get home, take it out to warm up a bit, then give it a try.
At least try this after you've had that initial taste that you're going to have to try immediately upon removing it from the wax.
Well done. A cheese to you.
- Jeff