Anyone got these both reels, Tranx 300 paddle handle (102mm) and curado 70? Can you please help me try to see if Tranx handle would fit curado without any modification, nut and lock nut too?

Curious as to why you would want a handle like that on that little reel?  If you want length, you can buy a  96mm Shimano handle, which fits with nothing extra to make it do so.  The Metanium XG handle fits perfectly and I believe they are around $35.00

Just curiosity, while I searched for met handle happened to see Tranx handle available at tacke trap as well. Even though this is a little reel but it is for lefty reel (curado71) which is not my usual hand. I fish all right reel but this one and want to be able to crank better. I think I cannot keep up with bass when need to and lost one nice bass recently. I can't even reel in buzzbait smooth enough ho finger. I don't have any of this problem with spinning reel so I figure longer handle might help me.

Just keep practicing. It will become natural before you know it. I switched to left hand baitcasters last year for bottom baits. 

Keep the reel off the rod and during the week just turn the handle as much as you can. At your desk at work or in the car at red lights. 

I should think the 96mm handle would help you.  It is a lot longer than the stock Curado 70/71 handle.

Got diy carbon handle from Chaina, I thought it's not suppose to be here for next week or so. Too bad at that time I ordered, I didn't think I'm gonna need long handle so I ordered 90mm handle for scorpion 70. 

I'll try this handle on 71 and see if it help.