Marcus, did you ever get back on your lake and have some success? I fish for lake bookies anywhere between the April opener and mid may, which means actual “ice out” could of been very recently or even many weeks ago, but we still catch fish (most of the time). My best year was fishing the 1st week of May, 2 months after iceout, but have also had good catches as late as mid May, 1 week after iceout.  Either way, the water temps were around 10c.

Note…..Brook Trout love sucker eggs and suckers spawn at iceout wherever they find water flowing into a lake, so look for a stream flowing INTO your lake and observe. If you see suckers, go for it. Suckers egg flies are my choice. 
 

Rayk

Like Will said, a 5wt is good general purpose fly rod. It’s my go to rod, unless I’m steelheading and in that case I fish a 7wt.

Does the older rod have no marking at all? Put the 5wt line on it and give it a try. If the rod seems stiff, I would assume it’s a heavier WT, if it feels to flexible, I would assume it’s a lighter WT. I say “assume” because “feel” can be subjective.

Ray