help with my gear. rod, reel combinations etc

Ive fished on and off the past few years and am only really getting serious about it this year. I have a bit of gear but need to invest and upgrade in some areas and am looking for info from people on here that have more knowledge than myself.

I will start with my beach casters, 1st is a century sre 16ft long I think, at the moment I am just using a mitchell reel its a freerunner 6600, cheap enough reel as far as I remember but seems to work well but id like something better for the century rod so reel suggestions please? (This will be my distance rod so good casting reel, fixed spool)

2nd beach rod is a Penn powergraph surf 12ft, my plan is to stick the mitchell reel on this but its labelled a multiplier rod and only has two jubilee clips to hold the reel. So do I buy something to convert to a fixed spool reel? Also looking to replace the line on the reel so suggestions on breaking strain and decent brand appreciated. (I will fish at closer range with this setup)

Thanks in advance and I have more info im after but will try get these sorted first

Any pictures of your setup? However, first plan of action is probably to change your line if you haven't fished for a while which I gather from your post. Fishing lines dont last forever, I change mine every year. Anyway, if you are not really sure what brand, strength, diameter etc. I suggest take what you have to your next tackle dealer. I dont know where you are based and the entire setup as you describe it here might need a few adjustments. Most tackle dealers can give you good advice what you might need and it's always your decision what you want to spend for your hobby. A word of advice though - don't go there on a payday, the temptations are overwhelming sometimes. Have a clear budget and let the dealer know how much you are prepared to spend and dont take a cent more with you. Good luck and hope to read your reports here soon!