It may be tough man...I appreciate that...but don't do it to yourself. don't climb on top of your layout either. That mistake has been made dozens of times.
The thing I can tell you 100% without fail is the hardest spot to reach will bethe place where you will experience the most issues. That's 45 years and 9 layouts telling you that; not to mention all the other layouts I'd advised on... Don't do it to yourself.
If you do true "L" girder there will be enough separation between joists to reach. I recommend 24 inches. You can get away with 18 if you are not a huge person. TEST your own fit. Make vertain you can reach everything, because sooner or later you will need to.
I'm giving you GREAT advice and guess what I did. My most difficult point to reach at only 26 inches away was a switch placed ON TOP OF A GRADE--another mistake. After many choice words to myself because I know better I changed my arrangement.
God I wish I listened to myself! :-) LESSON LEARNED, again, again. :-)
