it is perfectly safe*, if you take some simple notes, to use one wallet with two computers, just make use you always use coin control and send small change coins first when they have enough confirmations(medium priority).
change amounts are quite small, most of the time they are from 0,010xxxxx to 0,019xxxxx, you can always send to console - keypoolrefil 1000 before copying wallet.dat it will make your wallet bigger with 1000 change addresses
before deleting one wallet check if balance is equal to another by comparing output of - listaddressgroupings - typed in console, dump/import the missing address
there is an option to send change to custom address also
* - in fact you have double backup if one PC HDD fails, but you have double weak points if one PC is compromised by a trojan virus.
You are funny.
"Its perfectly safe you just have to
#1 create 1000 addresses in advance
#2 think which inputs to spend every time you create a transaction
#3 take extra caution against viruses."
Just use electrum, multibit HD or any other HD wallet.
