To collect research rewards regularly, the amount of GRC in your wallet is actually largely irrelevant. What most newer members don't realise is that your wallet's 'estimated time to earn reward' is based on staking weight only. Research mag plays a large role in your actual payment rate.

I have a magnitude of about 640 today, and have been paid out four times already, despite only having 1000ish GRC...

What we will be seeing is a massive drop in GRC/mag paid out as more members join the community, as is to be expected. If you look at the growth rate of compute contributed to some projects, there is an almost exponential trend over the last weeks.