I know that this might sound ridiculous, but I would like a serious answer: Would 10 untimed PTs with rigorous review be sufficient for developing speed?? In what ways have untimed PTs contributed to your success on LSAT preparations? How long did it take?
If it sounds ridiculous, that's only because it is ridiculous.
In seriousness and in general, no. There are two stumbling blocks on the LSAT: accuracy and speed. You have to answer the questions correctly within the time limit. Untimed practice is good for accuracy. Timed practice is good for speed. Usually accuracy has to precede
speed, which is the reason that people recommend starting out with untimed practice. But accuracy doesn't replace
Even so, if you're not far off finishing in 35 minutes anyway, then a greater understanding of the questions may help you speed up as well, which means that you may not need much timed practice after your untimed practice. But when I started with the LSAT, I was doing games sections in an hour (with perfect accuracy). The only way to get better was to watch my time and slowly speed up.