Recommendations for optimum use of the Googolplex?

I haven't rushed the build of the Googolplex, so I still have over 19 hours to go. From what I can gather from other threads, the Googolplex allows you to keep levelling up past level 60, and that combining this with use of the XP Collider and buying/selling Rat Trap Delivery Trucks allows to you level up quickly and gain donuts in the process.

Obviously, some people have experienced problems with this, but is the consensus that most people can now do this OK?

If so, does it matter when I start using the XP Collider? Should I do it before or after the Googolplex has finished building?

Thanks for tips and suggestions!