Just go ahead and get the HW 45 in .177 cal. (4.5mm) and later acquire the .20 cal. (5.0mm) and .22 ca. (5.5mm) spare barrels.
There is no way of tuning-down the HW 45. They come out as a single power output item. Even the US-destined Beeman P1 is just like the HW 45. Both are equally powerful. There is no weak HW 45 around as the pistol in .177 cal. has two power settings (the .20 and .22 have only one), only the first scale cocking is weak, but who needs it right?
My opinion is that you start with a basic .177 cal. HW 45 before moving on the caliber scale. In the States and Britain the .177 cal. HW 45's command a premium in the second-hand market, if that sort of thing interest you. In other words, the resale price of a .177 is higher than the price paid for it in factory-new condition! In fact they are becoming scarce. The .22 cal. are the most common HW 45s around and then the .20 cal. which command the highest price in both as a new basic pistol and as an accessory spare bbl.
Good luck!
Mack The Knife,
Count me in the IFG Team!
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