It really depends on what year you have. Some of the older ones had shorter bolts, and some of the newer ones had longer. On my Lazer, for instance; It has the shorter bolts (1"). When runnining doubles, I went and got longer bolts. However, I couldn't get 1/4" longer bolts of that size. I had to get 1/2" longer (1 1/2"). There is enough room up inside of the spindle to accomodate this much more thread, so in all actuality, I am running more thread to thread area than what I am when I'm running singles. Do NOT run doubles with any less than 3/4" thread UP INSIDE!
Yeah, I'm not that familiar with the Toros, and I'm not that familiar with the smaller ones (like the Exmark HP series), but I THINK '01 is when they went to the longer bolts on the full size Lazers, anyway. Mine is a 2000, and a friend of mine bought an '01, and his had the longer bolts.
If it dosent work try removing some washers till it does work. Not farmilar with your mower either but most have a few washers and 2 spacers. If they are closer to the top of the deck it will just take away some lift. Might try it, just a sudjustion