Hey DT havent been on much lately, anyways sorry Dugtrio didnt work out for ya but good to hear that youre using ScarfTran. the coverage DOES suck but if you get rid of anything that walls it it makes for a great late game sweeper!
Here's that set you asked for
Heatran @ Choice Scarf
Timid nature, Flash Fire
Hidden Power of your choice, Flamethrower and Earth Power are must haves and for the last slot you have lots of options. I prefer Overheat over other...
Hey dude how have you been?
Anyways this seems like a pretty good team so far. Regarding your dilema i would personally choose Magnezone over Jolteon for this team.
Also for your T-Tar problem maybe a Dugtrio with a good set could be the answer. it takes care of Rachi also which means you have...