First thing I do is talk you out of the gypsum. Just go all Calcium Chloride here to get up to ~60ppp Ca+.
If you want to go a la carte rather than a kit you could try this for a five gallon batch:
9 lb Best Malz pils malt
.25 lb Weyermann CaraFoam
4 oz Czech Saaz hop pellets (you may not need all four but NB does not list a specific AA%, only a range)
Do a single temp mash @ 150F and a 90 minute boil.
If the Saaz are 3.5% you will need two ounces for the bittering addition and one ounce @ 20 minutes. If they are lower than 3.5% you will have the extra ounce to compensate. Three ounces of 3.5%AA Saaz with a five gallon beer should get you to 40-42 IBU which is PU territory. No need in this small of a batch to sub for higher alpha hops IMO.
The Best pils malt should mash just fine with a single temp. Personally I always go decoction mash with this style of beer but you can save that for the future along with the floor-malted Bohemian pils malt. I like a lower mash temp and a small dose of the dextrin malt to get a combination of a clean, dry finish and a good mouth feel. Others may suggest omitting the dextrin and mashing higher, you can decide that for yourself. :cheers: