Although BSA already answered, I would like to add some info about 18inch wheels etc.
[Wheel] Standard 18inch rim and HED Carbon rim have same diameter, no difference. Weight is also very similar between these 2, but you can reduce weight with break rotor, rimtape, tube and tire. This might help for uphill. (We can go off topic easily with other weight saving mod, so I would stay within “Tire and wheel” in this thread). HED rim has some advantage in aerodynamics although it is hard to tell how much.
[Tire] Panalacer minits lite PT < Kojak < Marathon racer < Marathon Plus
← Lighter and Harder vs Longer life and More confortable ride →
I have never used Continential and IRC tire (for BD-1), but these 2 are also available (in some markets).
[Tube] Schwalbe SV4: 85g, MAXXIS UL-421: 60g
I found that CST is also offering Light Tube, but I have never used.
[Break roter] Original F:107g R:130g / Tektro F:80g R:102g (TR140-4 and TR160-4) / KCNC F:62g / R:74g (* 3rd party 160mm roter for rear has to be filed little bit to enlarge inner diameter). If you sometime have to use your break really really hard, I would not recommend lightest one.
[Other] Rimtape can be swapped with veloplug (veloplug.com/), veloplugs may save some weight, but the real advantage is that it has much much longer life.
If you are interested in weight saving, concerning cost and weight, Tektro roters might be well balanced solution. around 40US$, saves 55g of unsprang weight (if you do not have tool, or if you ask shop to change them it may cost more).
Concerning pure weight, it is obvious that 16inch 24spokes wheel is lighter than 18inch 36 (or 32) spokes wheel, but 18inch has advantage to go faster and has theoretically better ability to deal with bumps. So far, I do not have issue with top gear + 18inch wheel set , so I like 18inch in general, but I do not think everyone should go for 18 inch because people have different purpose and opinion in general.