BTW, that resistor-fix is prepared on Indivision AGA MK2. I have given that resistor the manual-soldering-friendly 0805-package. Most other parts on the board are 0402 (the stuff that you hardly see; size of fly spots).
However, that only seems to help the A4000D. I haven't seen good improvements on the A1200. On the 1200, a small chip-cooler on Alice appeares like the better option.