If you can grab the shrouds and they wiggle back and forth with a bit of slop they are too loose. If they are tight enough to go "Boing" when you strum them they are just about right. If you strum them and they go "Ping" they are too tight. When you raise and lower your mast
your forestay turnbuckle usually needs to be loosened to give you enough play to take out your clevis pin. So each time you step your mast you'll need to retighten your forestay. Again, "Ping" is too tight and if you consistently tighten your forestay too tight you could distort your fore chainplate or turn your boat
into a banana.
Adjusting your rigging
should be done while at the dock
on a calm day. Testing the rigging should be done while sailing. If you think you've got it right then take it out to sea, have someone take over the tiller and you lay down beneath the mast and sight up it. If there is a bend side to side then you need to go back in and readjust.
Congratulations on stepping the mast!