Thank you everyone for the replies. I will contact herbies to discusss specific sizes and shapes of big fat dots for my TBI subwoofer modules which have the following specs:
WIDTH 14.5 inches ( 368.3 mm ))
DEPTH 14.5 inches ( 368.3 mm )
HEIGHT 5.5 inches ( 139.7 mm ) no feet ( 7 inches w/spikes )
WEIGHT 15 lbs ( 6.8 kg )
I should note for the record that i have been at the audio game since 1989 and have tried a large variety of isolation products. After many years of expereimentation i prefer herbies products in general. This includes the gliders under speaker stands and herbies DBneutralizing smaller square pads to great positive effect under center channel speakers mounted in or on top of cabinets. These square dots are also superlative under smaller speakers on top of a number of different speaker stands. (they seem to sound best when used with sklyan's for some reason)
I also use tenderfeet judiciously under many of my components and baby booties under smaller power supplies. All work great and dont give a "mushy" or smearing type of sound.
This is the reason i posted here, having great success in the past. Whether its now wroth cost of 8 more fat dots is a personal choice.
I will also add that i also run a number of vintage amps and preamps, which have less than NASA quality metal cabinets. The tendfeet work well here but for some reason Isonodes seem to prefer that that application.
I have also used the type of cork product listed above and that is a trial and error process at best. Sometimes good sometimes neurtral and sometimes just ok. They are best IMO used under noisy inkjet printers as a fyi.
I always find it humorous that the two main sellers of these products for audio application claim to have "tuned them by ear". Id like to see what that method was