Hi Zielar
Waouhh impressive this speed! If you could choose the beginning and end of the search range, you could find pubkey #66 between 2 and 4 months. On the other hand the search is carried out randomly it makes random hashes on the PK of #64 #66 #67 #68 #69 #71 and #72 it can be faster as well as much longer depending on luck. Too bad this program could be largely optimized like choosing the hash range #66 as well as the random or sequential mode with your speed you could come across #66 in 1 month or 2 depending on luck.

Edit
Looking more closely at the operation of this utility and your speed, the proba are these
in 10 days on all the beaches by inserting the 6 pubkeys (I calculated for the first 6 # not 29)  you have a one in 148 chance of having one of the keys
in 20 days 1/74  1.35%
in 40 days 1/37  2.75%
in 80 days 1/18  5.5%
in 160 days 1/9  11%
in 320 days 1/4  25%
it remains arbitrary because luck can enormously speed up the process