Matching Fly line with bamboo rod

Since it's labeled 4wt, I'll assume it has modern guides so no need for a slim diameter line.  
But not all 4wt lines are created equal and neither are rods so you might want to try different brands, weight and styles to see what you and the rod likes. That's where a local fly shop can come in handy if they have demo lines.
Anyway, my 6'4'' likes Cortland 444 peach and Rio classic.
Since it's a small stream rod and you probably aren't going to be casting more than 30 ft., go with a double taper line.
That way you can turn the line over and use the other end once the first end gets worn out.
An old trick is to cut the double taper line in half and just use 45 ft of the line attached to you backing.
 

i ended up getting scientific angler master something or another.

had it out last weekend.  reallly smooth casting dries and small nymphs.  little tougher with BH nymphs under the float.