I got the astatc SWR meter and it was very easy to use. If you spend more than $20 on one, thats too much. Took me a while to get my antenna tuned correctly, but once it was dialed in, its been working great ever since. My tip is unscrewed almost 3/4 of an inch to an inch. It got to the point where I thought the SWR wasn't working until I started unscrewing the tip almost all the way.
I think I got mine for $15 of eBay. The one you picked should be fine.
1972 Commando on Tons & 40s