I think many recommend a Caerphilly as a good starting point for hard cheeses, because it doesn't need a lot of aging, allowing you to learn faster.... I have been making cheese for a year now, with no pH meter, and I find that learning the "Grip Test" is key to knowing when the cheese is done cooking.... Compressing a small ball of curds in your hand, to see how they mat together, and then teasing them apart with your thumb to see how easy they separate again.... gives great insight into whether it is time to proceed.... It is amazing what a difference 5 or 10 minutes make....
Pressing is an art, and not pressing too hard, too soon, is the biggest beginner mistake, I think (it certainly hurt my first attempts).... The weights in recipes may not apply to your mould, and cranking on too much weight too soon will trap whey in the paste, causing cracks and voids when it continues to acidify.... This can lead to a sour (acidic) taste, and a crumbly texture.... Make SURE you don't have a stream of whey running out, just dripping or weeping is the correct pressure.... Then increase with time, aiming to close the rind at 2 hours from starting to press.... except for Cheddars, of course, which require more pressure to knit....
I have resisted getting a pH meter because of what I have read about cleaning and calibrating them.... I know many would be lost without them, perhaps I just don't know what I am missing....
Bob