If you read this forum long enough you'll find a way to double what you've spent already.
You've got a good handle on it. What do you plan on using to level the 5er (side to side)? I just use 2x8 pressure treated wood planks. They're a lot cheaper than the plastic stacking Legos but they take more storage space and can be heavy when wet.
__________________
2023 Rockwood Signature 8262RBS
2016 Ford F-250 XLT SuperCrew, 6.2L, 4x4, 6'9" bed
2019 Rockwood Signature 8290BS (2019 - 2022)
2011 Rockwood Signature 8293SS (2015 - 2018)
2010 Rockwood Roo 23SS (2012 - 2014)