depends on tank size and what its filled with... OFC general warnings about your neighbours etc... HK Army shooting up their back yard is not a good example. but if you have plenty of space (or are contained in some way) and your neighbours are chill then its less of a worry.
don't put c02 on any decent markers, it will kill them.
don't waste your money on a custom 98 that you will replace after one visit to a site.
right... here we are, we have a mini GS or something,,, and a 68/4500 HPA tank.
its probably filled to 3k... you need to find a dive centre, or site that will fill it up for you as it can't be posted with any pressure.
you should easily get at least a bag of paint through it before it runs out... so long as you don't have massive leaks, and you take the bottle off / turn the ASA off in between use.
PLEASE be sensible in the garden,, shooting the neighbours cat might sound funny.. but its not.
Paintball will be open in a couple of weeks... so hopefully we can all get out and play then