No need to remove the motherboard to install the ZIP RAM, removing the drive/power supply carrier is enough. If you ordered the ZIPs from China and if they are supposed to be static column, be prepared for them to be fake (i.e. page mode zips that had their surface ground off and new fake info printed - I got 24 of those that I am now instead using with an Oktagon 2008. Took a while to figure out why the machine was crashing. I confronted the seller and got a significant refund)
I can add the Int2 modification and install either an Ultracapacitor or a Lithium coin cell holder (with diode) if you want me to.
Btw. 16 MHz A3000s are pretty rare. I think you can use the Super Buster rev 9 but you don’t need it unless you are doing Z3 DMA.
As stated above, the Super Buster 11 does not work with the motherboard clock set to 16 MHz. Possible solution: switch to a 25 MHz oscillator, jumper the motherboard accordingly, and hope that the 16 MHz 68030/68881 (not 68882 on the 16 MHz model) work. Alternate solution: get an accelerator
Btw if you stick with 16 MHz, then you could go with a 16.6667MHz crystal - that’s the actual speed rating of the 16 MHz parts. The motherboard/components are designed for 25 MHz so they won’t complain with that little speed increase.
Other items would be to correct the orientation of the SCSI termpower diode and adding a Polyswitch resettable (self healing) 1A fuse.