Welcome to the SS forum. I am relatively new to stacking as well...started about 18 months ago and have been very slow to add much to my stack due to financial woes.
Try to determine why you are stacking...what makes you believe that precious metals (pm) products are something worth sinking money into. Pardon the expression but it's sort of apropos in the current consolidating silver/gold market.
Anyway, if you are buying blobs (common, non-denomination, bullion bars), I would forget about PAMP or any other blobs that carry a high premium. Go for the lowest premium possible and wait to buy when the price is lower. There are some trends in the market because the market is driven largely by sentiment and fear and if you follow it closely (examining past charts and reading current smart objective perspectives), you should be able to more often than not gauge when the price is in the lower ranges.
If you are buying semi-numi coins as a short term investment, which is fine, that's trickier in most cases to figure out which coins will be winners and which losers. Hype from noisy used-car-salesmen-like precious metals sellers and stackers certainly can make a horrid-looking, terrible design, overpriced coin like the Zeus, a some what sought after coin. Then there are coins that are very appealing with a great design that may take a while (a couple of years) to get off the ground and sore...like the America the Beautiful 5 oz silver coins (namely the collector version) for example.
For me, someone who plans on storing my coins and blobs in the safety deposit box for a long time, diversification will be best for my strategy as I am not convinced that we will see a US dollar currency collapse in my lifetime nor will there be a SHTF scenario in my lifetime. Silver and gold will probably never back a major currency again and so its utility as a backer of a major currency just doesn't exist any more and never will in the foreseeable future. That said though, silver and gold will always be desired by some people and so you will always find someone to buy your blobs but keep in mind that when you sell to a dealer, they knock down the price and give you a dealer buy-back price which is less than spot. So, if the precious metals market takes 20 years to slowly come out of consolidation and you have a need to sell your blobs before then, you may be taking a bigger loss than you think because there are storage costs, taxes or VAT that you may be paying that you probably will not recoop, shipping costs paid, etc, etc. The point is, buying blobs doesn't ensure profit gain. At best, it may ensure that instead of buying that new stereo system that you really didn't need anyway, that you took a gamble on a sort of insurance policy that may be worthwhile if the pm markets recover and hold at the time you are planning to sell.
There's plenty of arguments on both sides about whether or not pm's are worth buying...get informed about all the arguments and be weary of the permabulls (those who are always telling anyone who takes them seriously that silver and gold prices will go to the moon very soon) and those who always assert that the value of gold and silver are dead forever. You can bet that both these extremists have a vested interest in pushing their rhetoric/propaganda. Read different sources and get as wide a range of smart opinions as possible.
Most importantly, enjoy the conversation here on the SS forum and take advantage of some of the many level-headed people here!