Sounds like a great idea at first - if you're not lifting your weight, restrict your downloads.
But, the problem is, everyone begins at a ratio of 0. And by your plan, that means everyone starts with a file size limit of 50mb.
Who wants a 50mb file?? Talk about crummy quality viewing. The only people who would want to download a 50mb file are those who need to just to get their ratio up to begin with. But, because nobody wants to download it, their ratio never really increases.
The thing I like about gt.ru is that people don't hold back on the quality (and hence filesize) of the shares. I think the filesize limiting might work against that
A better idea might be say
0.1 - 0.15 : maximum 1 download, no limit on filesize, but you can only download 50mb of that file (in other words, until you get over 0.15 ratio, you're stuck with only 50mb of the large file you started downloading.) This means people when they first start out will look for torrents that are in high demand to get over that hump asap - that's starts them out with the right habits, and it's good for everyone at gt.ru
Hmm, now that I re-read what you said, maybe that's what you meant all along? Should I still hit the submit button?…. yeah why not.