The best place to get all the info you will need regarding setting up a fridge pump and tanks is www.joewoodworker.com
I bought 3 units when I first went with this setup (only used 1) for $25 bucks from a used appliance place. Just normal fridge pumps are fine, I doubt the smaller pumps would be as good though.
FYI- don’t know if they say this on the JW site but remember to ask the place you buy from that the pump doesn’t have a thermal shut down switch.
Thanks for the info, Im definitely going to go to some used appliance stores and be asking them for some pumps next week.
The reason I asked about the smaller bar fridge type is because there is a few going on for sale on my local auction sites. Starting at $1 reserve as well so if they work, they’ll be a steal for the price 
Examples;
to be real honest i wouldnt waste my time…or money for that matter…the extra vacuum you get from a real pump makes a world of difference i promise you that…ask anyone that makes semi/complex parts on here they will tell you that a “real” pump is indeed alot better in the long run
what sort of extra vacuum do you get form a real pump? pulling 29" with a fridge pump is the same as pulling 29" with any other pump.
well my fridge pump pulls 27-28" every day with no worries.
complexity of the part has no bearing on the amount of vacuum the pump pulls.
I’ll say without hesitation I wouldn’t use the fridge pump to infuse a boat hull or anything larger than a auto hood. But it works JUST fine for everything I need it for.
i may or may not be wrong but i highly doubt you are going to pull 29hg from a fridge pump…i have a robinair and i dont even pull 29hg, nor did the yellowjacket my father had and it was quoted by the company to pull 15microns, my robinair is supposed to pull 50 microns
of course it depends on your relative height in to sea level…but im sure i am correct in saying that a fridge compressor most likely wont pull anywhere near 29hg…there is a reason why the “real” pumps cost more than fridge pumps…its not just some magical number someone just thought about for robinair/yellow jacket…etc…there is a reason they cost more just like there is a reason ferrari’s cost more than toyota’s…do your own investigation on google like i did and you will get the answers you seek about fridge pumps vs heating/ac, medical, other types of vacuum pumps or generators
google has lots and lots of information out there so just peek around
I measured just the other day (I’m at pretty high altitude Edmonton Alberta) but I was registering 25-26"…