Need some advice...

So I recently purchased a Wildcat MK3 compact in .25. I will be using the gun exclusively for squirrel hunting. I currently have a Yong Heng compressor and use it to direct fill my gun so it only runs just a few minutes so hopefully I will get a lot of life out of it. I would like to buy the smallest portable tank I could find so could use it in the field jut to top off the gun one or two times. I would like to find something that I could use the Yong Heng to fill.(Without running it for an hour). Also, it needs to fit in a small back pack. Does anybody make such a thing that's not crazy expensive? Can you guys point me in the right direction? 
 
You need something along the line of a small 90-100ci fill station I have a Ninja EZ Fill and love it but Benjamin, Air Venturi and others make them also. Mostly 350-$400 although since you have your own compressor you can probly get by with a Chinese CE approved tank instead of a DOT which should save you at least $100. Be sure to get a 4500psi tank or you will not be able to fill your gun completely. Also be sure you are getting a fill station valve capable of the fill and not a regulated paintball tank. Bigger is usually better if you don't have to carry it around but the 90 and 100ci will easily fit in a backpack.

My first Yong Heng has been running for two years now with only a couple of o-ring replacements needed.



https://www.bakerairguns.com/product/air-venturi-carbon-fiber-tank-with-ez-valve-4500-psi-100-cu-in/

https://www.amazon.com/pcp-tank-4500-psi/s?k=pcp+tank+4500+psi

This one is a bit large for some packs it is roughly twice the size of the 100ci tanks.

https://www.ebay.com/itm/CE-3L-4500psi-Carbon-Fiber-Air-Tank-High-Pressure-Fill-Station-With-Regulator-US/402260609335?hash=item5da899c937:g:ccAAAOSwmaBeu18n
 
I have a Guppy I use from JB, great little tank, 18cu ft and I can fill my MKii 300cc tank a good 5 times. Or my fill my Marauder 22/25 10 decent times. 

When you are ready to purchase a tank, figure out the size and do some calculations. Heres the link so you can figure out how many fills you will get from the tank.

https://www.airgunsofarizona.com/Tanks/FillCalc.html



Also, what Ive see on this board that a lot of people do is buy a large 4500psi tank, get it filled at a scuba/paint ball shop/fire station and then use it until 3k, then use their Yong Heng to get it from 3k to 4500 in intervals of 15 mins. 

So you would run the compressor for 15 mins, let it cool, repeat until your tank is topped off.