Any one have any tips? Suggestions? Notes that I screwed up by diluting it?
I've never used the temptu pros but it sounds like it's fine to dilute them with IPA if they're alcohol based.
The Tinsley transfers are pretty good and they can make whatever you design - it's good to have transfers for continuity if you are going to be needing to repeat it on a regular basis. You do need to powder them though, or flick/airbrush a bit of flesh tone over them to sink them in, they can be a bit shiny and new looking.
Depends what the budget is of the project.
For a cheap and cheerful transfer you can find the image you want and print it out then photocopy it. (This doesn't work on all photocopiers and I have no idea what makes it work and not work but it's trial and error!).
Cut out the image and place it on the skin in the right place. Saturate the paper with acetone and press (same process as for tinsley but acetone, not water!) and peel off. Ta da! You can then touch up with inks if you need to. Of course if there's any writing on the tattoo you have to make sure it's mirror image so it turns out the right way on the skin.
I have used this method to great effect on many small jobs - it's my best kept secret! (Well, not any more...)