Friction shifters and barrel adjusters
 

I recently installed a Friction bar end shifter for my front triple derailleur and shifting is working fine but was curious to know, do you feel there is any added benefit for installing an inline barrel shifter as well (no braze ons for standard barrel adjuster) ? In other words, is fine tuning cable tension important with a front friction shifter ? As always, thank you for your input.

Assuming you pulled most of the slack out of the cable and tightened the fastening bolt adequately when you installed the shifter, there is no need for a barrel adjuster with friction shifting. I have four bikes, all with friction front shifting and triple cranks. I've never used the barrel adjusters for anything but cable housing stops.

I have had a few inline barrel shifters in my tool box for years. The only bike I have needed one on is using a vintage Campy Rally derailleur. I would say buy a few and keep them in the box till ya need um...

I'll second the above. FD shifting when friction is pretty darn simple. You need a slack enough cable that the FD can relax completely for downshifts. (And you hardly need a barrel adjust to ensure slack.) Nice if there isn't more slack so you don't have to lift to start the shift but if you do, so what? (Well, things get a little more critical with old, large cable pull FDs, small barreled shifters with little pull and triple cranksets. Lever might fold all the way back and still not lift the chain onto the big ring.)

True, no need, but it does help make initial setup a little easier - make it a little too loose when you attach the cable and then tweak with the adjuster.

I was going to suggest this as well -- it may be useful to fine-tune cable slack at the fully relaxed end...but indeed not necessary.

Bike racers who competed during the era when down-tube shifters were the only game in town would sometimes deliberately leave the front derailleur cable with a good amount of slack. That meant that the front derailleur would shift the chain to the inner ring well before the left lever reached its forward limit. The benefit was that the lever was positioned in easy reach of the right thumb for quick and easy one-handed shifts of both derailleurs.

[Edit:] Just reread the OP and realized that the question has to do with bar-end shifters. Never mind!