Converting Rocky Mountain Thunderbolt to single speed

I ordered the Wheels MFG XD kit. It seems to get great reviews and comes with a narrow wide cog, so I can now continue using the brand new 2 ride chain I had put on the bike. It comes with an 18T cog, so I can play with gear ratio with the 4 chainrings I already have. A 28, 30, 30 oval, and 32 original. I do have a tensioner already, but I'm hoping to come across a gearing that doesn't require it. I've been without a SS so long now that I am far too excited to have ordered this kit and then getting on a SS once again. Being a full squish, this will be all new. All my other SS were fully rigid. Last one being a 2014 Kona Unit.

How well do you think an oval would work on a SS? I've never ridden one on any of my present bikes. The only oval I've ridden was the archaic biopace rings from yesteryear. If I go oval on this SS conversion, would it be advisable to use the tensioner to take the constant tightening and slackening of the chain?