Wow that was fast, thanks for you effort!
I am getting some different info from Q&A on a server with P: drive vs whats returned on the property in BigFix:
My original:
q: ((pathnames of it, ((size of it)/1000000) as string & " MB") of descendants of folder "P:\") whose (substring before " MB" of (item 1 of it) as Integer > 0)
A: P:\pagefile.sys, 4294 MB
A: P:\temp\com.bmc.patrol.patsdk.rsm.messageworkers.SolutionResolvedWorker1437838876073299459.tmp, 1 MB
A: P:\temp\com.bmc.patrol.patsdk.rsm.messageworkers.SolutionResolvedWorker7913561937873263406.tmp, 1 MB
A: P:\temp\IRG7B.tmp\PersistedStore\MpPersistedStore.bin, 7 MB
A: P:\temp\KB2729449_20121121_001221956-Microsoft .NET Framework 4 Client Profile-MSP0.txt, 10 MB
A: P:\temp\KB2736428_20130109_231551031-Microsoft .NET Framework 4 Client Profile-MSP0.txt, 11 MB
A: P:\temp\KB2736428_20130109_231551031-Microsoft .NET Framework 4 Extended-MSP1.txt, 2 MB
A: P:\temp\KB2737019_20121121_001521531-Microsoft .NET Framework 4 Client Profile-MSP0.txt, 10 MB
A: P:\temp\KB2742595_20130109_214529389-Microsoft .NET Framework 4 Client Profile-MSP0.txt, 11 MB
A: P:\temp\KB2742595_20130109_214529389-Microsoft .NET Framework 4 Extended-MSP1.txt, 2 MB
A: P:\temp\KB2789642_20130214_001032292-Microsoft .NET Framework 4 Client Profile-MSP0.txt, 12 MB
A: P:\temp\KB2804576_20130516_012930008-Microsoft .NET Framework 4 Client Profile-MSP0.txt, 13 MB
A: P:\temp\KB2832407_20130710_213525615-Microsoft .NET Framework 4 Client Profile-MSP0.txt, 13 MB
A: P:\temp\KB2835393_20130710_221444488-Microsoft .NET Framework 4 Client Profile-MSP0.txt, 14 MB
A: P:\temp\KB2840628v2_20130814_195947224-Microsoft .NET Framework 4 Client Profile-MSP0.txt, 15 MB
A: P:\temp\KB2840628_20130710_225020585-Microsoft .NET Framework 4 Client Profile-MSP0.txt, 14 MB
A: P:\temp\KB2858302v2_20131010_034055572-Microsoft .NET Framework 4 Client Profile-MSP0.txt, 16 MB
A: P:\temp\KB2858302v2_20131010_034055572-Microsoft .NET Framework 4 Extended-MSP1.txt, 2 MB
A: P:\temp\KB2861188_20131014_214708373-Microsoft .NET Framework 4 Client Profile-MSP0.txt, 16 MB
A: P:\temp\KB2898855v2_20140212_201511022-Microsoft .NET Framework 4 Client Profile-MSP0.txt, 17 MB
A: P:\temp\KB2901110v2_20140212_203019412-Microsoft .NET Framework 4 Client Profile-MSP0.txt, 17 MB
A: P:\temp\KB2901110v2_20140212_203019412-Microsoft .NET Framework 4 Extended-MSP1.txt, 3 MB
A: P:\temp\KB2931365_20140514_193022867-Microsoft .NET Framework 4 Client Profile-MSP0.txt, 18 MB
A: P:\temp\KB2972106_20141016_013731973-Microsoft .NET Framework 4 Client Profile-MSP0.txt, 20 MB
A: P:\temp\KB2972215_20140910_231644303-Microsoft .NET Framework 4 Client Profile-MSP0.txt, 19 MB
A: P:\temp\KB2978125_20141112_234655164-Microsoft .NET Framework 4 Client Profile-MSP0.txt, 20 MB
A: P:\temp\KB2979575v2_20141016_013050832-Microsoft .NET Framework 4 Client Profile-MSP0.txt, 19 MB
A: P:\temp\KB3023221_20150513_220111430-Microsoft .NET Framework 4 Client Profile-MSP0.txt, 22 MB
A: P:\temp\KB3032662_20150513_220503239-Microsoft .NET Framework 4 Client Profile-MSP0.txt, 22 MB
A: P:\temp\KB3037578_20150416_013652820-Microsoft .NET Framework 4 Client Profile-MSP0.txt, 21 MB
A: P:\temp\KB3037578_20150416_013652820-Microsoft .NET Framework 4 Extended-MSP1.txt, 3 MB
A: P:\temp\KB3048074_20150513_205830827-Microsoft .NET Framework 4 Client Profile-MSP0.txt, 21 MB
A: P:\temp\KB3072309_20150812_214124354-Microsoft .NET Framework 4 Client Profile-MSP0.txt, 23 MB
A: P:\temp\McAfeeLogs\MFEagent.msi.2014.08.07.18.26.15.log, 1 MB
A: P:\temp\Microsoft .NET Framework 3.5-KB2736416_20130110_043128400-Msi0.txt, 1 MB
A: P:\temp\Microsoft .NET Framework 3.5-KB2840629_20130711_004612640-Msi0.txt, 1 MB
A: P:\temp\Microsoft .NET Framework 3.5-KB2861697_20131010_073019225-Msi0.txt, 1 MB
A: P:\temp\MSI4578e.LOG, 3 MB
A: P:\temp\SEP12_INST.LOG, 1 MB
A: P:\temp\SEP_INST.LOG, 7 MB
A: P:\temp\WER1D66.tmp.hdmp, 2 MB
A: P:\temp\WER296A.tmp.hdmp, 2 MB
A: P:\temp\WER41E7.tmp.hdmp, 2 MB
A: P:\temp\WER57AF.tmp.hdmp, 2 MB
A: P:\temp\WER9FAE.tmp.hdmp, 2 MB
T: 41.332 ms
Too much info. So I move to your relevance:
q: (pathname of it, size of it / (1024*1024)) of descendants whose(size of it > 0 AND pathname of it as lowercase does not start with "p:\temp\") of folder "P:\"
A: P:$RECYCLE.BIN\S-1-5-21-2978336-1207586478-467891306-1105\desktop.ini, 0
A: P:$RECYCLE.BIN\S-1-5-21-2978336-1207586478-467891306-1274\desktop.ini, 0
A: P:$RECYCLE.BIN\S-1-5-21-2978336-1207586478-467891306-154585\desktop.ini, 0
A: P:$RECYCLE.BIN\S-1-5-21-2978336-1207586478-467891306-22221\desktop.ini, 0
A: P:$RECYCLE.BIN\S-1-5-21-2978336-1207586478-467891306-23824\desktop.ini, 0
A: P:$RECYCLE.BIN\S-1-5-21-2978336-1207586478-467891306-376035\desktop.ini, 0
A: P:\pagefile.sys, 4095
T: 39.795 ms
Much better, but to drop out the smaller size files I go to this:
q: ((pathname of it, size of it / (1024*1024)) as string & " MB") of descendants whose(size of it > 1000 AND pathname of it as lowercase does not start with "p:\temp\") of folder "P:\"
A: P:\pagefile.sys, 4095 MB
T: 38.814 ms
Ok data return looks good, from Q&A, but here is the data returned in BigFix:

And lastly, I have not setup you other property yet, but this is what it returns in Q&A:
q: (pathname of it, sum of sizes of files of it) whose(item 1 of it > 1 * 1024 * 1024) of descendant folders whose( pathname of it as lowercase does not start with "p:\temp\" ) of folder "P:\"
A: P:\temp, 461462817
T: 50.037 ms
Is this maybe because P:\temp is the only parent folder on the drive?
Thanks,
Scott