Pavel --
I listed to Latin #1. Generally it's quite impressive. It's hard to picture that you've only been playing DB for two years. You have built a very strong foundation in a short time!
When I'm backing people on a mid-tempo bossa-nova piece I'm always torn. On the one hand, I started playing latin music from a very "busy," conversational place and I love to go there. On the other hand, the basic pulse of bossa nova is the
half-note -- the dotted-quarter-and-eighth is an embellishment on that basic pulse.
Right now you're dotted-quarter-and-eighth bumping through it, playing roots and fifths. There's nothing wrong with that; it's common. See what would happen to this piece if you spent more time walking half-notes. You can literally walk through it, creating long, slow lines with harmonic movement, and not every note will need to be a root or fifth. Embellish with dotted-quarter-and-eighth and with more conversational elements as you feel the music asking for them. Make them a musical choice.
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Edit:
Here is a clip from a brand-new record with Stanley Clarke as a side-man on double-bass. As I'm sure you know, Mr. Clarke is the person most responsible for the rise of busy, conversational uptempo latin bass-playing. Check him playing half-note bossa on "Fly Me To The Moon."
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Your soloing is also very nice -- good melodic playing with appropriate use of space. There are intonation issues which I'm sure you have already spotted. My suggestion for development over the long term is to put more harmonic gaps in your lines -- if you are playing on the G string, sometimes find a note on the A string which makes sense.
But again, you sound very well on your way and the biggest thing for you is just minutes, hours, days, months and years on the instrument. Have fun and report back please!
Yeah, u right, sometimes I'm getting involved in to this dotted-quarter-and-eighth "****" too much... Actually during the rehearsals I tried to experiment with comping, I played not only with the halfs, but also this "Tumbao" thing: half-quarter-quarter(tied with the next half) etc. It's definitely makes sense to change the groove sometimes! Indeed u're right! About the intonation: it's my one of the biggest problems right now, but I'm practicing with a bow, trying to play more and more Franz Simandl études and exercises, hopefully it will bring some results ("in 20 years", as jokes the teacher of Mine - Vitold Rek 
