Yep, a project of +90 can be drag for sure. Readymag shines in small websites but if your project load is larger, it is likely you will start pushing its boundaries.
It is not that Readymag cannot handle bigger sites, but I wouldn’t expect things to be ‘hassle-free’ on a project of that scale.
It is odd they asked for ‘space available on PC’, that is unlikely to be related. Maybe the mean RAM and not the actual device storage?