In Java Mission Control 5.x, you could easily view the total size of allocated TLABs. See the "Allocation Summary" in the bottom right of this image.
In Java Mission Control 7.x, I can't find an easy way to find this high-level information. I can view TLABs in blocks, and get a rough idea of periods of heavy TLAB allocation, but I can't find the total TLABs allocated.

Is there a way in JMC 7.x to view the total size of TLABs allocated during the recording period?

Yes. Go to the Summary tab on the TLAB Allocations page. You'll need JMC 8.1.0+.