If you could ONLY STACK 1 silver/gold coin, What would it be and w...

This is something i think about sometimes and i can never come up with an answer. I like most stacker's enjoy buying lots of different types of bullion from Mints all over the world. We have the largest selection of bullion to pick from nowadays, there seems to be a new series released every other week. As a stacker with limited funds, this can leave me torn between buying that new series i like are buying silver to stay up to date with my date runs. 1st world problems are a bitch.

Every year i buy around 150 oz of silver, some years more but never less. Around 100 oz's are allocated to completing my series runs and 50 oz are for whatever i like. It seems that every year, my series runs grew giving me less to play. This stresses me out as i can not buy everything i want so i think to myself, ''if i could stack 1 series, what would i stack?''. Lets have a look at what i buy every year.

China Panda x15, Congo Gorilla x5, Mexican Libertad x5
Perth Kangaroo x5, Kookaburra x5, Koala x5, Wedge tailed Eagle x3
Perth Lunar 0.5 oz x50, 1oz x3 and 2oz x1, Niue Pandas x5
Somalian Elephant x5, Britannia x25 (min), Uk lunar x3 and 1 of each 2 oz Queens beasts

These are musts every year for the next 2 years, that is another story for another day. The total of this comes in at around 110 oz per year. This might seem like small potato's to some guys stacking this every month but this is my budget for silver and when i look at this list, there is nothing special on there. The libertads, kangaroos, kooks, koalas, brits, elephants, and queens beasts will not gain much premium over say 10-15 years. I see the Pandas, Perth & Uk lunars and Niue Pandas having a good chance to gain a good premium. I can see that my overall coin selection is very poor and stacking 1-2 coins might be the best way to max returns. It may not be as fun. This would bring me down to 2 coins to pick from, i do not entertain the idea of picking a coin i dont already stack. When i compare the 4 coins, china Panda's and Perth Lunars are the winners. These are the 2 coins i am always torn between picking. I like both...

If i was put on the spot and had to answer, i think i would have to go Perth mint Lunars. China Panda's are great coin, they are minted perfectly with no issues there, they arrive in capsules and can stacked in trays of 15 You will always gets over spot for Panda's and they are an easy sell. But they are minting in grams now and the mintage numbers are going up.
My reason for picking the Perth Lunar series would be you complete a set every 12 years, there are more sizes to pick from, they are easy to resale and will always sell for over spot. I also prefer the finish on the lunar series coin compared to a polished finishes.

This is something i would like to do in the future, i have my 5 year stacking plan to complete. I plan to build a base of silver for 5 years, than go more gold as it's easier to store/hide, then some cypto's are stocks if the price in down in a few years. I am on my 4th year of silver so still 2 stacking years to go, my plans will change in this time, its too long for them not to change.