Open passing needs to be considered. Take some advice from someone who has done TT for years. If there is no open passing, imo, then it will be inferior to other TT programs. Here is why. First session is always first come first in line. If a fast guy like Bill ends up in the back, he could never get in a good lap if he can only pass on the straights. Not one lap, all weekend, unless he lags WAY BACK and tries to make a big gap. If you have 5-10 guys doin the same thing, you might as well forget it. The pack will get strung way out, and the front guys won't even get in a fast lap. Passing is the only way to effectively deal with slow cars/drivers in the early sessions. Once the pack gets sorted, there should be very little passing because the guy in front of you is theoretically faster.
One more way to explain the problem with traditional 'pass on the straights only' events. Guys who are slow are slow in the corners. Anybody with a Big Bore/Viper can come out of a turn slow and drag race to the end of the straight. A faster driver can set up one or maybe two slower cars for a pass by coming out of the corner faster, but will be hard pressed to get in a 10/10th lap. TT events in NASA are decided by tenths, sometimes hundredths or thousandths of a second. One slow corner and you 'lose.'
One more thing, who says you will have 'novice' track guys in TT any more than racing? The rules already say you need either a racing license or other organization TT license. In NASA, again for instance, you have to be passed through four (4) levels of HPDE to get a TT license. That involves gradual introduction to passing and eventually open passing.
A lot of guys to TT instead of racing because of the 'wear and tear' of the racing events, which is expensive to all, and to some it seems pointless. Most of the top TT guys lay down their fastest lap in the first one or two laps per session, then get off. Your car doesn't get so hot, and the wear and tear is minimal compared to racing. Some guys don't want to convert their cars to race cars...with cages you lose the ability to safely operate on the street. That applies to almost all ACR owners.
If you limit TT to race drivers/cars, then you will exclude a big share of Viper drivers. If someone is nervous about doing TT, then they can stick with racing. I assume TT is trying to attract a 'different' group or drivers anyway.
Just my 2c.