Indeed..and there's the rub. Not having easy/cheap access to proper testing facilities means we often end up just doing things because someone else said they should work...without real proof it's going to work on your setup, or because it seems to make sense, or both. As I said before, I know all about that!! I've spent a bloody fortune on my supercharged V6 to make not much of an improvement. Given the costs and effort, it verges on the pathetic really, and I'm not happy to say that, but I'm willing to confess it.
Last time I was at the rollers I ended up swapping cams to do a back to back test. Good job too, because I could have fooled myself into thinking it was better on the one set when in reality, it was over 30bhp down. Thankfully, I have a good relationship with the owners but I'm guessing doing that would normally be very expensive in RR time or they would just say go away and come back when you've done your mods. One test I did do as well....just in case...was to do a power run with and without the air filter & pipework connected. Didn't make any difference whatsoever...which clearly indicated that the filter and ducts were in no way restricitve. This is the sort of test you ideally want to do on the TB.
The place I use normally charge £300 for a half day, and you can do what you like in that time. I'd think taking along a box of parts that you can quickly swap over like TBs, filters etc would be worthwhile...just so you know for sure. Plus, you'd get to see a proper power/torque curve so you can see if you end up making a gain in one place but a loss elsewhere - that happens a lot.
But, all that said, enjoy the tinkering, and here's hoping for a good result.
How big is the stock TB on the TS?? Unless it's smaller than 40mm then I'd not bother personally (back to the Jenvey data, 200bhp on a 26mm restrictor)...but I seem to be in a minority here
There's more than just absolute flow to consider as well - a bigger TB is going to have a bigger change of flow for small throttle changes, particularly when it's nearly shut, so per degree shift of the butterfly will have more effect on the bigger TB, so it'll feel more responsive most likely - that's great if that's what you want, but it might also make it more awkward to drive under certain conditions. Despite what we might think at times, they don't just throw these things together! Having been dicking about with aftermarket ECUs on some of my cars for far too long, getting the driveability right is the hard part. Best power is simple given a RR and an operator who has a clue. Making it nice to drive on partial throttle settings is a very different problem.
I'll get me coat......