there is a trade-off, but it doesn't help too much because of you take more time, you need more error correction which takes more qbits. the best trade-off probably comes from dropping the error correction to the point where you go from 99% reliability to 1% reliability. doing so will increase your rsa factor time from ~1 week to ~1 year and probably saves you ~an order of magnitude in qbits

The big thing that could change the numbers is more reliable qbits. Most of the calculations so far are done with qbits right at the edge of where error correction works (about 5x better than current qbits). if you get another 10x in qbit quality you probably drop the required qbits by ~100-1000x.