There are some slight
threading/size differences with some of the ufs sections between the two versions. The v1 came with an atty extender and a mouthpiece. The v2 came, instead, with a steel window and and the new top cap you mentioned.
In answer to your question (applies to both ufs versions): Yes, you can use the new top cap on a full-length ufs with a 'long-style' atty/carto and use your own drip tip.
Alternatively, you could:
Use the ufs in short mode by screwing the refill cap directly on the window. Then you can use standard length atties/cartos with the new style top cap and the drip tip of your choice.
Get a
ufs 510 extension, use the ufs full length with a normal length atty, the new top cap and your drip tip.
Your choices are really only dependent on what is included when you get the ufs, what you can get from resellers and how you wanna use it.