Now I have read though this post and a lot of sugestions have been made. I do not think that limiting research is a good idea. if you want to research for 1000 hours then you are going to have to protect that server. I have had a server running research for over 1000 hours now and it has never been cracked. Now if you are using your main server for research then it is easier for people to find your IP and crack it.
One sugestion I would make would be this right now when you overload password break .35 up to around 1.4 the resourses you use are the same as running a 1.4. here is an example.
Special Password Break 1.30368 / CPU 2607 / MEM 162960 This is a 0.358154 overloaded
Password Break 1.43307 / CPU 2866 / MEM 179134 This is not overloaded
So as long as I have the resources to run a higher password break I do not need the higher break to crack someone. What I would suggest is that it when you overload a lower version the resources to run it should be doubled so I would have to have twice the resources.