I have no problem doing advanced kinds of counting with a metronome by clapping, but when I try to do it on guitar, it doesn't really transfer onto it, I have trouble even doing simple things such as 1 eight notes, 2 sixteenth and then 1 eigth. (But I can still imitate song's beats and timings by listening to them) I'm wondering is this is a big problem for playing guitar :O, because I used to play piano and it was important.
practice strumming open strings accross the spectrum of tuplets. (If you work on this enough, as an added benefit your alternate picking should get much faster as well) practice jumping back n forth btw pairs of (5 and 6) every click then (6 and 7) then (7 and 8) then (8 and 9) then (9 and 10) \and so forth. Alternate btw/ having your focus on 1. (keeping each set of tuplets evenly dispersed/spaced) 2.) (picking w/o any stress in your arm) and 3.) picking as fast as you can. I recomend starting out at 40 B.P.M. or less b/c I guarantee you if you start off doing these things @ 100 B.P.M. right of the bat you wont be learning the time feel and effortless alternate picking that these exercises are intended to facilitate.