I would just go with the API kit , then purchase a phosphate and KH/GH kit seperately. Most of the tests in these kits are only useful for cycling but they are needed... at first. I never check nitrites nor ammonia once tank is matured. The pH is better measured with a pen, so I don't use this one either. Others find the pH test satisfactory for them. The only one I check frequently out of the master kit is nitrates. I also keep an eye on phosphates, so I consider this test kit important for my high tech tank. For shrimp keeping it's essential to know your KH and GH, so that kit is important. Iron I don't test for. It's hard to get an accurate reading on it, no matter what kit you use. Iron is consumed so quickly when using the right chelate for your pH. (EDTA vs. DTPA) Chlorine is needed by plants in vary minute amounts, but I don't test for it. Calcium is another I don't test for but leave it to my GH booster to supply ample amounts.
I would invest in a tds pen if you are serious about shrimp keeping. I use this to determine when I need to do a water change on my shrimp tanks. On my high tech tank, I use nitrate levels to determine my water changes.
So you have the master API kit for like $20, then add about $10 each for phosphate and the KH/GH kit which brings you to a total of just over $40 with taxes/shipping.