If you can find one of the old SIMM Doublers for 72 pin SIMMs, you can stick two of them in the Q605/LC475. Of course, you won't be able to close the lid...
I actually tested that with the HP D4893 128MB SIMMs. I don't know if it will work with the Memory Master's. Some of them seem to wire the /RAS and /CAS up differently from each other.
I would be interested to know whether those will work in the PM6100. The D4893A don't work in the 6100 because the way Apple paired the four RAS lines in the SIMM sockets doesn't work with the way the /RAS and /CAS lines are associated on the D4893A.
I'm guessing these are what you got:
https://www.ebay.com/itm/151421400795
These are the ones I used with the SIMM Doubler. Now if I just knew the brand of the SIMM Doubler....
https://www.ebay.com/itm/151555126294