Firt, upgrade the ROMs in your 2091. 6.1 are no good, Get the 7.0 upgrade.
The A2000 can be fairly powerful with an 040 or 060 accelerator, but also add a graphics card. I think the GVP m card is still available new from Software Hut. You might also want a FF/SD for the video that gets passed through - that depends on your uses and the monitor being used.
I hope your A2000 has a 6.x motherboard. You will have all sorts of problems with 4.x.
Good luck