Rhythm is the basis for the rest of music.
My right hand technique is what sets me apart from every other guitar player.

Those that have been able to integrate drums/rhythm into their guitar playing are easily recognizable.
McLaughlin and Konokol
DiMeola started on drums
et cetera

cool. same thing here. my left hand is a bit retarted,
ergo my nervous system doesn't really work and it's very slow, because of an accident.
so i started to develop a playing style on the guitar with my right hand,
that nobody i know can mimic and makes up for the lack of movement with my left hand

I definitely agree, rhythm is absolute foundation to music.

I started with drums and only played them for years. After awhile I picked up piano and guitar but I tend to incorporate a drummers mind set into them, definitely guitar anyway.

When I started playing guitar I started to do percussive drum beats on the body of my acoustic. It blends well with my reggae/jam style. That definitely was attributed to the fact that I was a drummer first. My guitar playing isn't near the likes of Andy McKee or John Butler though haha

Hey shpongled, well firstly this reply might go on a bit also and you may have got your answer already, but I was also searching for my own answers and found this so I thought I would reply, I've never spoke on things like this before, so hope it's helpful...I might be wrong but it seams we are opposite in our approach to music, or our learnings anyway...I started messing with drums from an early age, pots and pans in my nans kitchen to start...my mom thought drums were to much noise so I was given an electric guitar on my 11th birthday...I messed with bongos when small but went through a frustrating period of knowing what I wanted...but couldn't find my answers...many bands later...and after being introduced to the recording process I started doing my own stuff...and buying myself a drum kit..then electric drums..and along the journey somewhere in my late teens I required a sliver flute...the guitars were a pain to find what I wanted and waisted a lot of time money and frustrations on that also...I got a beautiful Gibson SG when 16 but never appreciated it till many years later...my tastes were mixed up and swapping around instruments till I hit certain feels just came with time...but never started out to write something...if I did..it never turned out like I expected...sometimes better sometimes worse and sometimes quirky...I also from an early age wrote singer songwriter stuff..but because my influences were broad this also confused me and I started trying to box things togeather and make sense of what I was doing...it was very confusing and sub divided all my ideas until I had so many off shoots I didn't know what to do...and that still applies today...somewhere in the late 90,s I also got into synths and other electronic hardware...that all so sent me sideways and more off shooting and stuff started off...I did have a piano in the house from an early age..but nobody played it...just small memory's of my grandad drunk playing roll out the barrel.....but I always messed with it...so I guess without knowing I was learning....anyway I don't have any proper musical advise or terminology for you, but my guess is you came from a learned instrument with its rules...and when you think about righting your always going to revert back to that...the same as driving a car or something...so you just need to use what you have...it would be difficult for me to sit and write something before I hit strum or blow an instrument..but something sparks an idea and I try to capture that...but most often it turn into its own...the music writes itself....my arrangements are rubbish because the idea starts and finishes...and I'm lazy for the hard work of beginnings and endings and all that..and that's where my problems lye....if I was you I would just try not to think to much...and if you have a good idea on an instrument....don't think about writing...just play a few notes and see if you can ride the tune....I've also been making bamboo flutes the last couple of years...and never before having those half notes you Carnot get on a silver flute, it's great...but still I want to write more than I do...but I don't have a choose...only when I'm sparked and it flows can I be happy with something...but look at it like cooking...throw in the ingredients and see what it tastes like...I think you can make anything fit with anything else...but it's where your heads at...and how much your thinking about it....it can be amazing or a pile of ****e...but I've got my own issues with it all so I'm just sharing my thoughts...I also met a singer who came from a classical background im not saying you are but she was in turmoil because she was swapping her soprano voice falsetto and her natural voice she couldn't right her own songs and that seamed to haunt her a little bit, but what a lovely voice...I think we musicians all have our problems...so it's good you share yours and give me the chance to rattle a little bit about mine....I just don't think there is a easy answer...the odd few might be 100% happy but I doubt it....

To me when you spend time practicing one instrument, you don't spend time practicing the other. So when you've spent the past couple days playing guitar your piano skills will be dull.

I play multiple instruments and I find that the more frequently I play one instrument, the skills that I have developed for the other instrument start to fade but if I were to pick up that instrument again I could remember the basics.