Extremely minimal access to the store could be nice (like incredibly small, just to get a taste), but I think you would be better off introducing another form of reward for raking up game time on DTK servers.
You could set skin rewards for players that achieve a certain amount of playtime:
- 100 hours: Special hat
- 300 hours: Special skin
- 500 hours: Super special skin
Other incentives could exist to drum up traffic for lower pop servers like accumulating hours at 1.5x the normal rate.
As far as I know, CS:GO does have limits to the amount of skins and props that can be pre-cached. This is affected by the map that is currently running, the store (and all models that are precached there) and other plugins that may be running on the servers, that don't run on others (zombies vs death match). Once this limit is reached, I believe the servers crash (and the limit is stupidly low).
I am unsure if there are reward systems in place for playing on the servers already, but it could be interesting to introduce something new. I know a lot of other server have this and there seems to be some success to it. It just can't compromise the financial aid that DTK currently receives from donations in any way, as that is what keeps it all running (and Old Mate Squally of course
).