hey there,
i found this for your SD card solution. looks like an all in one thing that plugs on to the IDE port, so no need for cables! i might investigate something like this myself soon as compact flash cards are becoming a bit thin on the ground these days...
http://amigaonthelake.com/amsider-sd-adapter/and i found this for your 8meg ram expansion - that'll go in the trapdoor bay of your 1200
https://amigastore.eu/en/698-amiga-1200-8mb-fast-ram-expansion.htmla CF card adapter won't fit an SD card, as the two are different both physically and logically. where a CF card adaptor wins is it can be totally passive, and not need any chippery at all to interface with the IDE port, as the card itself is an IDE device. So the adapter can be super cheap.
The SD card has a different interface, so i'd imagine it at least needs a buffer chip to turn the 16bit IDE transfers into a 1 or 2 bit serial-like feed into and out of the SD card itself. But SD cards are easy to come by these days so that's where SD cards win.
whats the aim of the game? set yourself up a WHDLoad machine?
[edit] i just saw the word "accelerator" in your original post. the only option right this second are these i guess, unless anyone else has any ideas?
https://icomp.de/shop-icomp/en/shop/product/ACA12xx.html