Don't get the steel pitot mount, They are ridiculously heavy (and over priced).
This is what I have in my -7:
https://www.aircraftspruce.com/catalog/inpages/alumpitotmast12-04764.php
You need to think hard about how you are running the wiring, so that you can get everything pre-drilled and fitted before you close the skins. Vans has the conduit, and I definitely recommend a run of that out to the tips.
I put snap bushings in 3 separate holes near the spar, two for running the airbrake line, and one for the power to the pitot. On the other wing you will probably need to add some more snap bushings in the same position for getting the wiring out to the temp probe that you will likely add near one of the access panels.
Fuel tank caps are probably worth investigating also. The ones that come with the kit are miserable. The flanges suck (hard to bend to the right shape), and the locking mech is super stiff. They also don't have key lock. I have the Newton version you used to be able to get from Van's, but apparently Van's don't sell them any more, but you may be able to get them from Newton. They are a great piece of quality gear. Main thing is to get something with a profiled flange to match the wing curve.
Probably need to get some proseal too (can't remember if that ships with the kit), and thing about getting some type of dispenser and anything else you need to build the tanks. Throw the proseal in the fridge to extend the shelf life.
Might be worth getting the mount kit for your autopilot servo, and thinking about how the wires will be run and where you will need to put adel clamps etc.
Same applies for the pitot temp controller. This is way easier to sort out before you put the bottom skins on.
I'm guessing the rear spar service bulletin kit now comes with the wing kit. Just don't forget to install it before you get that bottom skin on. I'm sure the RV-7 instructions are still as they came off the initial printing press.
Heaps of 3/32 clecoes. I'm a big believer in using lots of clecoes if you want to ensure you end up with a quality product.
A tungsten bucking bar is also a must if you don't already have one. Some of those bottom skin rivets can be a beast to buck unless you have a tungsten bar.
That's about all that comes to mind for now.
Good luck.
Tom.
RV-7