ak****a jain,
Welcome to the forum.  I know I've posted this before, but for a nice clean back side with 100% penetration on SS, I strongly recomment Solar Flux type B.  Both Solar Flux and back purging with argon will drive out the oxygen, float out unwanted oxides, and dissipate the heat on the back of the weld.  If not, you get a sugary, porous weld, and burn-thru.  The front of the weld will look good, but you can see the difference when inspecting the back side.

All things being equal, you will obtain the same quality weld with either.  The reason I push the Solar Flux is because it's less expensive, faster set-up, than building purging blocks and hooking up gas lines and containement of gas, etc, etc.  Here's the link to there website, but they give me a pretty good price on the stuff so PM me or just post in the forum and I'll see what I can do to hook you up.  Solar Flux has gotten me out of some serious binds in the past, and I really feel like I owe them.  It especially works very good on thin SS material.  When I say thin, I mean really thin, like down to .010".  TIG, max. 25 amps, .020" tungsten, and just maybe a .010" tungsten that I specially ordered for a specific project.  Hope this helps.

Take Care,
Steve