The transactions for the masternode(s) are "locked" when you start your wallet. (pivxd reads the transaction list from the masternode.conf file).

If you comment or remove those lines from the masternode.conf and restart the wallet, transactions that were reserved for the masternode will be able to stake. After those transactions stake, they will not be able to be used for a masternode so you would need to go through the process of setting up the masternode again.

I think the the block rewards would be about the same or maybe a tad more than the equivalent time staking. The three+ day wait is a bit painful considering that the block reward is scheduled to halve when we reach "PoS Phase X: [blocks 648000-Infinite] 05 PIV (90% SEESAW ~ 10% BUDGET)". Certain upgrades need a restart and then all who run masternodes need to wait some time. This is longer than before but there are more masternodes now than when I was running this before.

Myself, I had been staking for the last while since running masternodes needs a bit more effort and attention. I put some pivx back into masternodes for this upgrade a bit over 3 days ago, thinking I would get a bit more in this last month with the higher reward. It's hard to say what the best decision would be there's another 21+ days to go until the block reward halving.
 
With 2037 masternodes, a masternode payout should about about every 1.4 days.