49 storeys would be a bit taller for the area. The closest nearby height precedents would be at the Sherbourne & Wellesley intersection, where 159SW is 36s and the older Verve condo is 39s.
However, just a thought but I don't believe NJS Capital will be the ones to ultimately realize this project in the end. From what I gather of their operations, they manage smaller apartment blocks and look for opportunities to add value in their investments. Which gives me the impression that they're possibly looking at this site to upzone for high intensification potential and then flip it for profit.
It's possible that this proposal may end up around the low to mid-40s range, but for NJS it's all just going to be house money to be determined.