Puredata sample playback machine hosted on an RPi. Questions on performance.

So I have the idea of making a sample playback machine in pure data. Essentially there will be say 4 sample loops that will all playback at the same time and they can be combined and played all at the same time or individually or any combination. There will be physical switches to hear the individual tracks.

So my question is in regards to developing this in PD. I am long time beginner to PD. I can BS my way through it but I still have a lot of learning to do.

So what would lead to better performance (especially when hosted on a Rpi)...

1.) Developing a mixer in PD that automatically plays back each samples at the same time on their own separate tracks and the physical switches are essentially track mutes which one will disengage to hear the sounds.

2.) Each "track switch" will control the start/stop of each sample. That would need some logic where when you say start sample 2 while sample 1 is on it will not start playback until sample 1 gets back to 0 and starts looping again.

3.) or is there some other way I should be exploring?

Besides the performance concerns the other feature I want to employ is a tempo knob that will increase the speed of the samples playback (all samples will be effected at the same rate) but I do not want to pitch up the playback. Which I know PD can do but have to figure out how. So that may have some influence on the means of development.

Any ideas are welcome.