for Beethoven Sonata No. 5 in c minor 1st movement?

I am performing Beethoven's Sonata No. 5, Op. 10 No. 1 in c minor 1st Movement soon and I have come across a problem. I am having trouble finding a that would suit these particular measures. The measures are m. 86-89 and m. 263-266. These measures appear right after the 4 measures of eighth notes that are played together in the left and right hand in different octaves. When I come across m. 86-89 and m. 263-266, it calls for a "sf" at the beginning of each measure after the syncopated rhythm. I was wondering if there would be a that I could play these measures while hitting the "sf" with a finger such as the thumb, index, or middle finger. I would like for the to not put the "sf" on my pinky because I cannot play it loud enough. Please list and tell me a for this syncopated rhythm to where I can end up with my thumb, index, or middle finger on the "sf" note on the beginning of each these listed measures. Thank you very much! ♪