Looking for RTA software with logging

I currently use SMAART for on-site real time RTA, but recently have been asked to do some scientific-ish measurements for a buddy of mine who builds firearms suppressors.

SMAART has a very nice and very smooth spectrograph visual, but when it comes to recording the data I am pretty much limited to doing a screen capture. This obviously limits me to the data that is visible in the frame, which is only about 5 seconds.

I've tested a few other programs, but haven't found anything I am really happy with.

The only requirements are data logging of the spectral output over a time period of say 20 seconds, peak average dB SPL for that same time (A weighted), and able to calibrate the measurement to dB SPL.

I have already blown my wad on buying SMAART, so a somewhat affordable pricetag would also be nice.

Thanks.

Basically this is what I am looking to record: