Free sapce on CDR

I have a mini CD (185MB) capacity. I read a couple places that I can get the CD size by using: and by looking at "ATIP start of lead out: 101567 (22:36-17)" and using the sector size i.e. 2048 I can calculate 101567 * 2048 = 208009216 bytes. This is the over reported CDR capacity (the CD has 185 MB written on it) that can be used for overburn. The CDR I have is written in multisession mode so the output of "cdrecord -toc -dev=0,0,0" is:

Using generic SCSI-3-mmc CD-R driver (mmccdr). Driver flags : SWABAUDIO Drive buf size : 1234944 = 1206 KB 01 00 00 01 00 00 00 00 01 AA 01 01 00 00 00 00 Current Secsize: 2048 ATIP info from disk: Indicated writing power: 5 Is not unrestricted 1995-2001 J?rg Schilling TOC Type: 1 = CD-ROM scsidev: '0,0,0' scsibus: 0 target: 0 lun: 0 Linux sg driver version: 3.1.24 Using libscg version 'schily-0.5' atapi: 1 Device type : Removable CD-ROM Version : 0 Response Format: 1 Vendorinfo : 'NEC ' Identifikation : 'NR-7900A ' Revision : '1.08' Device seems to be: Generic mmc CD-RW. Disk sub type: Medium Type B, low Beta category (B-) (4) ATIP start of lead in: -11644 (97:26-56) ATIP start of lead out: 101567 (22:36-17) Disk type: Short strategy type (Phthalocyanine or similar) Manuf. index: 10 Manufacturer: Lead Data Inc. first: 1 last 4 track: 1 lba: 0 ( 0) 00:02:00 adr: 1 control: 4 mode: 2 track: 2 lba: 21994 ( 87976) 04:55:19 adr: 1 control: 4 mode: 2 track: 3 lba: 29196 ( 116784) 06:31:21 adr: 1 control: 4 mode: 2 track: 4 lba: 36398 ( 145592) 08:07:23 adr: 1 control: 4 mode: 2 track:lout lba: 97938 ( 391752) 21:47:63 adr: 1 control: 4 mode: -1 CD-Text len: 4

How can I find the used space (in bytes) on the CDR? Once I have that I can compare the amount of bytes I want to write to and deceide accordingly. Thanks for your help

-AJ