Here is my suggestion remove the sump and place in the new spot then put the brace back. transfer water from old tank to new tank with basically everything rock sand and livestock..... then do your plumbing on your new tank which should buy you a week and in this time keep adding water like 5g a day to your tank which will give you a chance to fill it slowly as for lights just rig them up so they work and then worry about perfecting them afterwards. oh yea and the question about leaks with the overflow? you can dump buckets through your overflow to see if there
are any leaks..... if youve done plumbing before then you know to do things right the first time, use extra glue so there are tight seals and the rest is history, only thing that might complicate things is if you have a cl system and in which case transfer the sump first anyways do plumbing and then transfer everything over then start filling slowly like 30g every few days and you're golden!
