Is it permissible for a Muslim to seek guidance from his Lord through Istikhara, and if he doesn't feel anything, to write "yes" and "no" on two pieces of paper and then choose one of them?

Istikhara is recommended, and casting lots for it was not reported from the Prophet (peace be upon him) nor from any of his Companions. The person performing Istikhara should do what his heart feels at ease with. If he does not feel this ease, he should proceed with the matter as long as his heart is not turned away from it. If his heart is turned away from it, he should abandon it, based on the Prophet's (peace be upon him) supplication in the Istikhara prayer: "Then turn it away from me and turn me away from it, and ordain for me good wherever it may be."