[Latitude 28]

I can answer your first two questions.  Here is the pressure gauge that I use https://www.amazon.com/gp/product/B07KYB...UTF8&psc=1.  You holes look a little smaller than mine though. The spring loaded valve cap...you will read you pressures through the cap leaving it in place.  I use these....https://www.amazon.com/gp/product/B014VCY3S2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1.  When you get a TPMS you will have to remove the cap.